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LH EMISSION CONTROL SYSTEMS 25 - 1

EMISSION CONTROL SYSTEMS

TABLE OF CONTENTS

page page

N-BOARD DIAGNOSTICS . . . . . . . . . . . . . . . . . . . 1VAPORATIVE EMISSION CONTROLS . . . . . . . . . 20

page

MONITORED SYSTEMS. . . . . . . . . . . . . . . . . . . . 12

EXHAUST GAS RECIRCULATION (EGR)SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

ON-BOARD DIAGNOSTICS

TABLE OF CONTENTS

page

ESCRIPTION AND OPERATIONSYSTEM DESCRIPTION . . . . . . . . . . . . . . . . . . . . 1DIAGNOSTIC TROUBLE CODES . . . . . . . . . . . . . . 1DIAGNOSTIC TROUBLE CODE

DESCRIPTIONS . . . . . . . . . . . . . . . . . . . . . . . . . 2

TRIP DEFINITION . . . . . . . . . . . . . . . . . . . . . . . . 14MONITORED COMPONENT. . . . . . . . . . . . . . . . . 14NON-MONITORED CIRCUITS . . . . . . . . . . . . . . . 18HIGH AND LOW LIMITS . . . . . . . . . . . . . . . . . . . . 19

SPECIFICATIONS
LOAD VALUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
ESCRIPTION AND OPERATION

YSTEM DESCRIPTION

PERATIONThe Powertrain Control Module (PCM) monitorsany different circuits in the fuel injection, ignition,

mission and engine systems. If the PCM senses aroblem with a monitored circuit often enough tondicate an actual problem, it stores a Diagnosticrouble Code (DTC) in the PCM’s memory. If theode applies to a non-emissions related component orystem, and the problem is repaired or ceases toxist, the PCM cancels the code after 40 warmupycles. Diagnostic trouble codes that affect vehiclemissions illuminate the Malfunction Indicator LampMIL). Refer to Malfunction Indicator Lamp in thisection.Certain criteria must be met before the PCM

tores a DTC in memory. The criteria may be a spe-ific range of engine RPM, engine temperature,nd/or input voltage to the PCM.The PCM might not store a DTC for a monitored

ircuit even though a malfunction has occurred. Thisay happen because one of the DTC criteria for the

ircuit has not been met. For example, assume theiagnostic trouble code criteria requires the PCM toonitor the circuit only when the engine operates

between 750 and 2000 RPM. Suppose the sensor’soutput circuit shorts to ground when engine operatesabove 2400 RPM (resulting in 0 volt input to thePCM). Because the condition happens at an enginespeed above the maximum threshold (2000 rpm), thePCM will not store a DTC.

There are several operating conditions for whichthe PCM monitors and sets DTC’s. Refer to Moni-tored Systems, Components, and Non-Monitored Cir-cuits in this section.

NOTE: Various diagnostic procedures may actuallycause a diagnostic monitor to set a DTC. Forinstance, pulling a spark plug wire to perform aspark test may set the misfire code. When a repairis completed and verified, use the DRB scan tool toerase all DTC’s and extinguish the MIL.

Technicians can display stored DTC’s. Refer toDiagnostic Trouble Codes in this section. For DTCinformation, refer to charts in this section.

DIAGNOSTIC TROUBLE CODES

DESCRIPTIONA Diagnostic Trouble Code (DTC) indicates the

PCM has recognized an abnormal condition in thesystem.

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25 - 2 EMISSION CONTROL SYSTEMS LH

DESCRIPTION AND OPERATION (Continued)

Remember that DTC’s are the results of a sys-em or circuit failure, but do not directly iden-ify the failed component or components.

OTE: For a list of DTC’s, refer to the charts in this

Fig. 1 Data Link (Diagnostic) Connector

ection.

OPERATION

BULB CHECKEach time the ignition key is turned to the ON

position, the malfunction indicator (check engine)lamp on the instrument panel should illuminate forapproximately 2 seconds then go out. This is done fora bulb check.

OBTAINING DTC’S USING DRB SCAN TOOL(1) Connect the DRB scan tool to the data link

(diagnostic) connector. This connector is located inthe passenger compartment; at the lower edge ofinstrument panel; near the steering column.

(2) Turn the ignition switch on and access the“Read Fault” screen.

(3) Record all the DTC’s and “freeze frame” infor-mation shown on the DRB scan tool.

(4) To erase DTC’s, use the “Erase Trouble Code”data screen on the DRB scan tool. Do not erase anyDTC’s until problems have been investigatedand repairs have been performed.

IAGNOSTIC TROUBLE CODE DESCRIPTIONS

(M) Check Engine Lamp (MIL) will illuminate during engine operation if this Diagnostic Trouble Code wasrecorded.

(G) Generator Lamp Illuminated

GENERICSCAN TOOL

CODE

DRB SCAN TOOL DISPLAY DESCRIPTION OF DIAGNOSTIC TROUBLE CODE

P0106 (M) Barometric Pressure Out of Range MAP sensor input voltage out of an acceptable rangedetected during reading of barometric pressure at key-on.

P0107 (M) Map Sensor Voltage Too Low MAP sensor input below minimum acceptable voltage.

P0108 (M) Map Sensor Voltage Too High MAP sensor input above maximum acceptable voltage.

P0112 (M) Intake Air Temp Sensor Voltage Low Intake air (charge) temperature sensor input below theminimum acceptable voltage.

P0113 (M) Intake Air Temp Sensor Voltage High Intake air (charge) temperature sensor input above themaximum acceptable voltage.

P0116 A rationatilty error has been detected in the coolant tempsensor.

P0117 (M) ECT Sensor Voltage Too Low Engine coolant temperature sensor input below theminimum acceptable voltage.

P0118 (M) ECT Sensor Voltage Too High Engine coolant temperature sensor input above themaximum acceptable voltage.

P0121 (M) TPS Voltage Does Not Agree WithMAP

TPS signal does not correlate to MAP sensor signal.





GENERICSCAN TOOL

CODE


P0122 (M) Throttle Position Sensor Voltage Low Throttle position sensor input below the acceptablevoltage range.

P0123 (M) Throttle Position Sensor VoltageHigh

Throttle position sensor input above the maximumacceptable voltage.

P0125 (M) Closed Loop Temp Not Reached Time to enter Closed Loop Operation (Fuel Control) isexcessive.

P0130 1/1 O2 Sensor Heater Relay Circuit An open or shorted condition detected in the ASD or CNGshutoff relay control ckt.

P0131 (M) 1/1 O2 Sensor Shorted To Ground Oxygen sensor input voltage maintained below normaloperating range.

P0132 (M) 1/1 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normaloperating range.

P0133 (M) 1/1 O2 Sensor Slow Response Oxygen sensor response slower than minimum requiredswitching frequency.

P0134 (M) 1/1 O2 Sensor Stays at Center Neither rich or lean condition is detected from the oxygensensor input.

P0135 (M) 1/1 O2 Sensor Heater Failure Oxygen sensor heater element malfunction.

P0136 1/2 O2 Sensor Heater Relay Circuit An open or shorted condition detected in the ASD or CNGshutoff relay control ckt.



P0139 (M) 1/2 O2 Sensor Slow Response Oxygen sensor response not as expected.

P0140 (M) 1/2 O2 Sensor Stays at Center Neither rich or lean condition is detected from the oxygensensor.


P0143 1/3 O2 Sensor Shorted To Ground Oxygen sensor input voltage maintained below normaloperating range.

P0144 1/3 O2 Sensor Shorted To Voltage Oxygen sensor input voltage maintained above normaloperating range.

P0145 1/3 O2 Sensor Slow Response Oxygen sensor response slower than minimum requiredswitching frequency.

P0146 1/3 O2 Sensor Stays at Center Neither rich or lean condition is detected from the oxygensensor.

P0147 1/3 O2 Sensor Heater Failure Oxygen sensor heater element malfunction.


P0152 (M) 2/1 O2 Sensor Shorted To Voltage Oxygen sensor input voltage sustained above normaloperating range.

P0153 (M) 2/1 O2 Sensor Slow Response Oxygen sensor response slower than minimum requiredswitching frequency.





GENERICSCAN TOOL

CODE






P0159 2/2 O2 Sensor Slow Response Oxygen sensor response slower than minimum requiredswitching frequency.



P0165 Starter Relay Control Circuit An open or shorted condition detected in the starter relaycontrol circuit.

P0171 (M) 1/1 Fuel System Lean A lean air/fuel mixture has been indicated by anabnormally rich correction factor.

P0172 (M) 1/1 Fuel System Rich A rich air/fuel mixture has been indicated by anabnormally lean correction factor.

P0174 (M) 2/1 Fuel System Lean A lean air/fuel mixture has been indicated by anabnormally rich correction factor.

P0175 (M) 2/1 Fuel System Rich A rich air/fuel mixture has been indicated by anabnormally lean correction factor.

P0178 Water in Fuel Sensor Voltage TooLow

Flex fuel sensor input below minimum acceptable voltage.

P0179 Flex Fuel Sensor Volts Too High Flex fuel sensor input above maximum acceptablevoltage.

P0182 CNG Temp Sensor Voltage Too Low Compressed natural gas temperature sensor voltagebelow acceptable voltage.

P0183 CNG Temp Sensor Voltage Too High Compressed natural gas temperature sensor voltageabove acceptable voltage.

P0201 (M) Injector #1 Control Circuit An open or shorted condition detected in control circuit forinjector #1 or the INJ 1 injector bank.



P0204 (M) Injector #4 Control Circuit Injector #4 or INJ 4 injector bank output driver stage doesnot respond properly to the control signal.

P0205 (M) Injector #5 Control Circuit Injector #5 output driver stage does not respond properlyto the control signal.

P0206 (M) Injector #6 Control Circuit Injector #6 output driver stage does not respond properlyto the control signal.





GENERICSCAN TOOL

CODE


P0207 Injector #7 Control Circuit Injector #7 output driver stage does not respond properlyto the control signal.




P0300 (M) Multiple Cylinder Mis-fire Misfire detected in multiple cylinders.

P0301 (M) CYLINDER #1 MISFIRE Misfire detected in cylinder #1.






P0307 (M) CYLINDER #7 MISFIRE Misfire detected in cylinder #7




P0320 No Crank Referance Signal at PCM No reference signal (crankshaft position sensor) detectedduring engine cranking.

P0325 Knock Sensor #1 Circuit Knock sensor (#1) signal above or below minimumacceptable threshold voltage at particular engine speeds.

P0330 Knock Sensor #2 Circuit Knock sensor (#2) signal above or below minimumacceptable threshold voltage at particular engine speeds.

P0340 (M) No Cam Signal At PCM No fuel sync

P0350 Ignition Coil Draws Too MuchCurrent

A coil (1-5) is drawing too much current.

P0351 (M) Ignition Coil # 1 Primary Circuit Peak primary circuit current not achieved with maximumdwell time.



P0354 (M) Ignition Coil # 4 Primary Circuit Peak primary circuit current not achieved with maximumdwell time (High Impedance).

P0355 (M) Ignition Coil # 5 Primary Circuit Peak primary circuit current not achieved with maximumdwell time (High Impedance).

P0356 (M) Ignition Coil # 6 Primary Circuit Peak primary circuit current not achieved with maximumdwell time (high impedance).





GENERICSCAN TOOL

CODE


P0357 Ignition Coil # 7 Primary Circuit Peak primary circuit current not achieved with maximumdwell time (high impedance).

P0358 Ignition Coil # 8 Primary Circuit Peak primary circuit current not achieved with maximumdwell time (high impedance).

P0401 (M) EGR System Failure Required change in air/fuel ration not detected duringdiagnostic test.

P0403 (M) EGR Solenoid Circuit An open or shorted condition detected in the EGRsolenoid control circuit.

P0404 (M) EGR Position Sensor Rationality EGR position sensor signal does not correlate to EGRduty cycle.

P0405 (M) EGR Position Sensor Volts Too Low EGR position sensor input below the acceptable voltagerange.

P0406 (M) EGR Position Sensor Volts Too High EGR position sensor input above the acceptable voltagerange.

P0412 Secondary Air Solenoid Circuit An open or shorted condition detected in the secondaryair (air switching/aspirator) solenoid control circuit.

P0420 (M) 1/1 Catalytic Converter Efficiency Catalyst 1/1 efficiency below required level.

P0432 (M) 1/2 Catalytic Converter Efficiency Catalyst 2/1 efficiency below required level.

P0441 (M) Evap Purge Flow Monitor Insufficient or excessive vapor flow detected duringevaporative emission system operation.

P0442 (M) Evap Leak Monitor Medium LeakDetected

A small leak has been detected in the evaporativesystem.

P0443 (M) Evap Purge Solenoid Circuit An open or shorted condition detected in the EVAP purgesolenoid control circuit.

P0455 (M) Evap Leak Monitor Large LeakDetected

A large leak has been detected in the evaporative system.

P0456 Evap Leak Monitor Small LeakDetected

A small leak has been detected in the evaporativesystem.

P0460 Fuel Level Unit No Change OverMiles

No movement of fuel level sender detected.

P0461 Fuel Level Unit No Changeover Time No level of fuel level sender detected.

P0462 Fuel Level Sending Unit Volts TooLow

Fuel level sensor input below acceptable voltage.

P0463 Fuel Level Sending Unit Volts TooHigh

Fuel level sensor input above acceptable voltage.

P0500 (M) No Vehicle Speed Sensor Signal No vehicle speed sensor signal detected during road loadconditions.

P0505 (M) Idle Air Control Motor Circuits Replace

P0522 Oil Pressure Sens Low Oil pressure sensor input below acceptable voltage.

P0523 Oil Pressure Sens High Oil pressure sensor input above acceptable voltage.

P0551 (M) Power Steering Switch Failure Incorrect input state detected for the power steeringswitch circuit. PL: High pressure seen at high speed.





GENERICSCAN TOOL

CODE


P0600 (M) PCM Failure SPI Communications No communication detected between co-processors in thecontrol module.

P0601 (M) Internal Controller Failure Internal control module fault condition (check sum)detected.

P0604 Internal Trans Controller Transmission control module RAM self test fault detected.-Aisin transmission.

P0605 Internal Trans Controller Transmission control module ROM self test fault detected-Aisin transmission.

P0622 (G) Generator Field Not SwitchingProperly

An open or shorted condition detected in the generatorfield control circuit.

P0645 A/C Clutch Relay Circuit An open or shorted condition detected in the A/C clutchrelay control circuit.

P0700 (M) EATX Controller DTC Present This SBEC III or JTEC DTC indicates that the EATX orAisin controller has an active fault and has illuminated the

MIL via a CCD (EATX) or SCI (Aisin) message. Thespecific fault must be acquired from the EATX via CCD or

from the Aisin via ISO-9141.

P0703 (M) Brake Switch Stuck Pressed orReleased

Incorrect input state detected in the brake switch circuit.(Changed from P1595).

P0711 Trans Temp Sensor, No Temp RiseAfter Start

Relationship between the transmission temperature andoverdrive operation and/or TCC operation indicates a

failure of the Transmission Temperature Sensor. OBD IIRationality.

P0712 Trans Temp Sensor Voltage Too Low Transmission fluid temperature sensor input belowacceptable voltage.

P0713 Trans Temp Sensor Voltage TooHigh

Transmission fluid temperature sensor input aboveacceptable voltage.

P0720 Low Output SPD Sensor RPM,Above 15 MPH

The relationship between the Output Shaft Speed Sensorand vehicle speed is not within acceptable limits.

P0740 (M) Torq Con Clu, No RPM Drop atLockup

Relationship between engine and vehicle speedsindicated failure of torque convertor clutch lock-up system

(TCC/PTU sol).

P0743 Torque Converter Clutch Solenoid/Trans Relay Circuits

An open or shorted condition detected in the torqueconverter clutch (part throttle unlock) solenoid control

circuit. Shift solenoid C electrical fault - Aisin transmission

P0748 Governor Pressur Sol Control/TransRelay Circuits

An open or shorted condition detected in the GovernorPressure Solenoid circuit or Trans Relay Circuit in JTEC

RE transmissions.

P0751 O/D Switch Pressed (Lo) More Than5 Minutes

Overdrive override switch input is in a prolongeddepressed state.

P0753 Trans 3-4 Shift Sol/Trans RelayCircuits

An open or shorted condition detected in the overdrivesolenoid control circuit or Trans Relay Circuit in JTEC RE

transmissions.





GENERICSCAN TOOL

CODE


P0756 AW4 Shift Sol B (2-3) FunctionalFailure

Shift solenoid B (2-3) functional fault - Aisin transmission

P0783 3-4 Shift Sol, No RPM Drop atLockup

The overdrive solenoid is unable to engage the gearchange from 3rd gear to the overdrive gear.

P0801 Reverse Gear Lockout Circuit Openor Short

An open or shorted condition detected in the transmissionreverse gear lock-out solenoid control circuit.

P01192 Inlet Air Temp. Circuit Low Inlet Air Temp. sensor input below acceptable voltage

P01193 Inlet Air Temp. Circuit High Inlet Air Temp. sensor input above acceptable voltage.

P1195 (M) 1/1 O2 Sensor Slow During CatalystMonitor

A slow switching oxygen sensor has been detected inbank 1/1 during catalyst monitor test. (was P0133)

P1196 (M) 2/1 O2 Sensor Slow During CatalystMonitor


P1197 1/2 O2 Sensor Slow During CatalystMonitor


P1198 Radiator Temperature Sensor VoltsToo High

Radiator coolant temperature sensor input above themaximum acceptable voltage.

P1199 Radiator Temperature Sensor VoltsToo Low

Radiator coolant temperature sensor input below theminimum acceptable voltage.

P1281 Engine is Cold Too Long Engine coolant temperature remains below normaloperating temperatures during vehicle travel (Thermostat).

P1282 Fuel Pump Relay Control Circuit An open or shorted condition detected in the fuel pumprelay control circuit.

P1288 Intake Manifold Short RunnerSolenoid Circuit

An open or shorted condition detected in the short runnertuning valve circuit.

P1289 Manifold Tune Valve Solenoid Circuit An open or shorted condition detected in the manifoldtuning valve solenoid control circuit.

P1290 CNG Fuel System Pressure TooHigh

Compressed natural gas system pressure above normaloperating range.

P1291 No Temp Rise Seen From IntakeHeaters

Energizing Heated Air Intake does not change intake airtemperature sensor an acceptable amount.

P1292 CNG Pressure Sensor Voltage TooHigh

Compressed natural gas pressure sensor reading aboveacceptable voltage.

P1293 CNG Pressure Sensor Voltage TooLow

Compressed natural gas pressure sensor reading belowacceptable voltage.

P1294 (M) Target Idle Not Reached Target RPM not achieved during drive idle condition.Possible vacuum leak or IAC (AIS) lost steps.

P1295 No 5 Volts to TP Sensor Loss of a 5 volt feed to the Throttle Position Sensor hasbeen detected.

P1296 No 5 Volts to MAP Sensor Loss of a 5 volt feed to the MAP Sensor has beendetected.

P1297 (M) No Change in MAP From Start ToRun

No difference is recognized between the MAP reading atengine idle and the stored barometric pressure reading.





GENERICSCAN TOOL

CODE


P1298 Lean Operation at Wide OpenThrottle

A prolonged lean condition is detected during Wide OpenThrottle.

P1299 (M) Vacuum Leak Found (IAC FullySeated)

MAP Sensor signal does not correlate to Throttle PositionSensor signal. Possible vacuum leak.

P1388 Auto Shutdown Relay Control Circuit An open or shorted condition detected in the ASD or CNGshutoff relay control ckt.

P1389 No ASD Relay Output Voltage AtPCM

No Z1 or Z2 voltage sensed when the auto shutdownrelay is energized.

P1390 (M) Timing Belt Skipped 1 Tooth or More Relationship between Cam and Crank signals not correct.

P1391 (M) Intermittent Loss of CMP or CKP Loss of the Cam Position Sensor or Crank Positionsensor has occurred. For PL 2.0L

P1398 (M) Mis-Fire Adaptive Numerator at Limit PCM is unable to learn the Crank Sensor’s signal inpreparation for Misfire Diagnostics. Probable defective

Crank Sensor.

P1399 Wait To Start Lamp Cicuit An open or shorted condition detected in the Wait to StartLamp circuit.

P1403 No 5 Volts to EGR Sensor Loss of 5v feed to the EGR position sensor.

P1476 Too Little Secondary Air Insufficient flow of secondary air injection detected duringaspirator test.(was P0411)

P1477 Too Much Secondary Air Excessive flow of secondary air injection detected duringaspirator test (was P0411).

P1478 (M) Battery Temp Sensor Volts Out ofLimit

Internal temperature sensor input voltage out of anacceptable range.

P1479 Transmission Fan Relay Circuit An open or shorted condition detected in the transmissionfan relay circuit.

P1480 PCV Solenoid Circuit An open or shorted condition detected in the PCVsolenoid circuit.

P1482 Catalyst Temperature Sensor CircuitShorted Low

Catalyst temperature sensor circuit shorted low.

P1483 Catalyst Temperature Sensor CircuitShorted High.

Catalyst temperature sensor circuit shorted high.

P1484 Catalytic Converter OverheatDetected

A catalyst overheat condition has been detected by thecatalyst temperature sensor.

P1485 Air Injection Solenoid Circuit An open or shorted condition detected in the air assistsolenoid circuit.

P1486 (M) Evap Leak Monitor Pinched HoseFound

LDP has detected a pinched hose in the evaporative hosesystem.

P1487 Hi Speed Rad Fan CTRL RelayCircuit

An open or shorted condition detected in the controlcircuit of the #2 high speed radiator fan control relay.

P1488 Auxiliary 5 Volt Supply Output TooLow

Auxiliary 5 volt sensor feed is sensed to be below anacceptable limit.

P1489 (M) High Speed Fan CTRL Relay Circuit An open or shorted condition detected in the controlcircuit of the high speed radiator fan control relay.





GENERICSCAN TOOL

CODE


P1490 (M) Low Speed Fan CTRL Relay Circuit An open or shorted condition detected in control circuit ofthe low speed radiator fan control relay.

P1491 Rad Fan Control Relay Circuit An open or shorted condition detected in the radiator fancontrol relay control circuit. This includes PWM solid state

relays.

P1492 (M,G) Ambient/Batt Temp Sen Volts TooHigh

External temperature sensor input above acceptablevoltage.

P1493 (M,G) Ambient/Batt Temp Sen Volts TooLow

External temperature sensor input below acceptablevoltage.

P1494 (M) Leak Detection Pump Sw orMechanical Fault

Incorrect input state detected for the Leak DetectionPump (LDP) pressure switch.

P1495 (M) Leak Detection Pump SolenoidCircuit

An open or shorted condition detected in the LeakDetection Pump (LDP) solenoid circuit.

P1496 (M) 5 Volt Supply, Output Too Low 5 volt sensor feed is sensed to be below an acceptablelimit. ( < 4v for 4 sec ).

P1498 High Speed Rad Fan Ground CTRLRly Circuit

An open or shorted condition detected in the controlcircuit of the #3 high speed radiator fan control relay.

P1594 (G) Charging System Voltage Too High Battery voltage sense input above target charging voltageduring engine operation.

P1595 Speed Control Solenoid Circuits An open or shorted condition detected in either of thespeed control vacuum or vent solenoid control circuits.

P1596 Speed Control Switch Always High Speed control switch input above maximum acceptablevoltage.

P1597 Speed Control Switch Always Low Speed control switch input below minimum acceptablevoltage.

P1598 A/C Pressure Sensor Volts Too High A/C pressure sensor input above maximum acceptablevoltage.

P1599 A/C Pressure Sensor Volts Too Low A/C pressure sensor input below minimum acceptablevoltage.

P1680 Clutch Released Switch Circuit

P1681 No I/P Cluster CCD/J1850Messages Received

No CCD/J1850 messages received from the clustercontrol module.

P1682 (G) Charging System Voltage Too Low Battery voltage sense input below target charging voltageduring engine operation and no significant change in

voltage detected during active test of generator outputcircuit.

P1683 SPD CTRL PWR Relay; or S/C 12vDriver CKT

An open or shorted condition detected in the speedcontrol servo power control circuit. (SBECII: ext relay).

P1684 The battery has been disconnected within the last 50starts.

P1685 Skim Invalid Key The engine controler has received an invalid key from theSKIM.





GENERICSCAN TOOL

CODE


P1686 No SKIM BUS Messages Received No CCD/J1850 messages received from the Smart KeyImmobilizer Module (SKIM).

P1687 No MIC BUS Message No CCD/J1850 messages received from the MechanicalInstrument Cluster (MIC) module.

P1693 DTC Detected in Companion Module A fault has been generated in the companion enginecontrol module.

P1694 Fault In Companion Module No CCD/J1850 messages received from the powertraincontrol module-Aisin transmission.

P1695 No CCD/J1850 Message From BodyControl Module

No CCD/J1850 messages received from the body controlmodule.

P1696 (M) PCM Failure EEPROM Write Denied Unsuccessful attempt to write to an EEPROM location bythe control module.

P1697 (M) PCM Failure SRI Mile Not Stored Unsuccessful attempt to update Service ReminderIndicator (SRI or EMR) mileage in the control module

EEPROM.

P1698 (M) No CCD/J1850 Message From TCM No CCD/J1850 messages received from the electronictransmission control module (EATX) or the Aisin

transmission controller.

P1719 Skip Shift Solenoid Circuit An open or shorted condition detected in the transmission2-3 gear lock-out solenoid control circuit.

P1756 GOV Press Not Equal to Target @15-20 PSI

The requested pressure and the actual pressure are notwithin a tolerance band for the Governor Control System

which is used to regulate governor pressure to controlshifts for 1st, 2nd, and 3rd gear. (Mid Pressure

Malfunction)

P1757 GOV Press Not Equal to Target @15-20 PSI

The requested pressure and the actual pressure are notwithin a tolerance band for the Governor Control System

which is used to regulate governor pressure to controlshifts for 1st, 2nd, and 3rd gear (Zero Pressure

Malfunction)

P1762 Gov Press Sen Offset Volts Too Loor High

The Governor Pressure Sensor input is greater than acalibration limit or is less than a calibration limit for 3

consecutive park/neutral calibrations.

P1763 Governor Pressure Sensor Volts TooHi

The Governor Pressure Sensor input is above anacceptable voltage level.

P1764 Governor Pressure Sensor Volts TooLow

The Governor Pressure Sensor input is below anacceptable voltage level.

P1765 Trans 12 Volt Supply Relay CTRLCircuit

An open or shorted condition is detected in theTransmission Relay control circuit. This relay supplies

power to the TCC>

P1899 (M) P/N Switch Stuck in Park or in Gear Incorrect input state detected for the Park/Neutral switch.

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ONITORED SYSTEMS

PERATIONThere are new electronic circuit monitors that

heck fuel, emission, engine and ignition perfor-ance. These monitors use information from various

ensor circuits to indicate the overall operation of theuel, engine, ignition and emission systems and thushe emissions performance of the vehicle.

The fuel, engine, ignition and emission systemsonitors do not indicate a specific component prob-

em. They do indicate that there is an implied prob-em within one of the systems and that a specificroblem must be diagnosed.If any of these monitors detect a problem affecting

ehicle emissions, the Malfunction Indicator (Checkngine) Lamp will be illuminated. These monitorsenerate Diagnostic Trouble Codes that can be dis-layed with the check engine lamp or a scan tool.The following is a list of the system monitors:• EGR Monitor• Misfire Monitor• Fuel System Monitor• Oxygen Sensor Monitor• Oxygen Sensor Heater Monitor• Catalyst Monitor• Evaporative System Leak Detection MonitorFollowing is a description of each system monitor,

nd its DTC.Refer to the appropriate Powertrain Diagnos-

ics Procedures manual for diagnostic proce-ures.

XYGEN SENSOR (O2S) MONITOREffective control of exhaust emissions is achieved

y an oxygen feedback system. The most importantlement of the feedback system is the O2S. The O2Ss located in the exhaust path. Once it reaches oper-ting temperatures of 300° to 350°C (572° to 662°F),he sensor generates a voltage that is inversely pro-ortional to the amount of oxygen in the exhaust.he information obtained by the sensor is used toalculate the fuel injector pulse width. This main-ains a 14.7 to 1 air fuel (A/F) ratio. At this mixtureatio, the catalyst works best to remove hydrocarbonsHC), carbon monoxide (CO) and nitrous oxide (NOx)rom the exhaust.

The O2S is also the main sensing element for theGR, Catalyst and Fuel Monitors.The O2S may fail in any or all of the followinganners:• Slow response rate• Reduced output voltage• Dynamic shift• Shorted or open circuits

Response rate is the time required for the sensor toswitch from lean to rich once it is exposed to a richerthan optimum A/F mixture or vice versa. As the sen-sor starts malfunctioning, it could take longer todetect the changes in the oxygen content of theexhaust gas.

The output voltage of the O2S ranges from 0 to 1volt. A good sensor can easily generate any outputvoltage in this range as it is exposed to different con-centrations of oxygen. To detect a shift in the A/Fmixture (lean or rich), the output voltage has tochange beyond a threshold value. A malfunctioningsensor could have difficulty changing beyond thethreshold value.

OXYGEN SENSOR HEATER MONITORIf there is an oxygen sensor (O2S) DTC as well as

a O2S heater DTC, the O2S fault MUST be repairedfirst. After the O2S fault is repaired, verify that theheater circuit is operating correctly.

Effective control of exhaust emissions is achievedby an oxygen feedback system. The most importantelement of the feedback system is the O2S. The O2Sis located in the exhaust path. Once it reaches oper-ating temperatures of 300° to 350°C (572 ° to 662°F),the sensor generates a voltage that is inversely pro-portional to the amount of oxygen in the exhaust.The information obtained by the sensor is used tocalculate the fuel injector pulse width. This main-tains a 14.7 to 1 Air Fuel (A/F) ratio. At this mixtureratio, the catalyst works best to remove hydrocarbons(HC), carbon monoxide (CO) and nitrogen oxide(NOx) from the exhaust.

The voltage readings taken from the O2S are verytemperature sensitive. The readings are not accuratebelow 300°C. Heating of the O2S is done to allow theengine controller to shift to closed loop control assoon as possible. The heating element used to heatthe O2S must be tested to ensure that it is heatingthe sensor properly.

The O2S circuit is monitored for a drop in voltage.The sensor output is used to test the heater by iso-lating the effect of the heater element on the O2Soutput voltage from the other effects.

EGR MONITORThe Powertrain Control Module (PCM) performs

an on-board diagnostic check of the EGR system.The EGR monitor is used to test whether the EGR

system is operating within specifications. The diag-nostic check activates only during selected engine/driving conditions. When the conditions are met, theEGR is turned off (solenoid energized) and the O2Scompensation control is monitored. Turning off theEGR shifts the air fuel (A/F) ratio in the lean direc-tion. The O2S data should indicate an increase in the

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2S concentration in the combustion chamber whenhe exhaust gases are no longer recirculated. Whilehis test does not directly measure the operation ofhe EGR system, it can be inferred from the shift inhe O2S data whether the EGR system is operatingorrectly. Because the O2S is being used, the O2Sest must pass its test before the EGR test.

ISFIRE MONITORExcessive engine misfire results in increased cata-

yst temperature and causes an increase in HC emis-ions. Severe misfires could cause catalyst damage.o prevent catalytic convertor damage, the PCMonitors engine misfire.The Powertrain Control Module (PCM) monitors

or misfire during most engine operating conditionspositive torque) by looking at changes in the crank-haft speed. If a misfire occurs the speed of therankshaft will vary more than normal.

UEL SYSTEM MONITORTo comply with clean air regulations, vehicles are

quipped with catalytic converters. These converterseduce the emission of hydrocarbons, oxides of nitro-en and carbon monoxide. The catalyst works besthen the air fuel (A/F) ratio is at or near the opti-um of 14.7 to 1.The PCM is programmed to maintain the optimum

ir/fuel ratio of 14.7 to 1. This is done by makinghort term corrections in the fuel injector pulse widthased on the O2S output. The programmed memorycts as a self calibration tool that the engine control-er uses to compensate for variations in engine spec-fications, sensor tolerances and engine fatigue overhe life span of the engine. By monitoring the actualir-fuel ratio with the O2S (short term) and multiply-ng that with the program long-term (adaptive) mem-ry and comparing that to the limit, it can beetermined whether it will pass an emissions test. If

malfunction occurs such that the PCM cannotaintain the optimum A/F ratio, then the MIL will

e illuminated.

ATALYST MONITORTo comply with clean air regulations, vehicles are

quipped with catalytic converters. These converterseduce the emission of hydrocarbons, oxides of nitro-en and carbon monoxide.Normal vehicle miles or engine misfire can cause a

atalyst to decay. A meltdown of the ceramic core canause a reduction of the exhaust passage. This canncrease vehicle emissions and deteriorate engineerformance, driveability and fuel economy.The catalyst monitor uses dual oxygen sensors

O2S’s) to monitor the efficiency of the converter. Theual O2S’s strategy is based on the fact that as a cat-
lyst deteriorates, its oxygen storage capacity and its
efficiency are both reduced. By monitoring the oxy-gen storage capacity of a catalyst, its efficiency canbe indirectly calculated. The upstream O2S is used todetect the amount of oxygen in the exhaust gasbefore the gas enters the catalytic converter. ThePCM calculates the A/F mixture from the output ofthe O2S. A low voltage indicates high oxygen content(lean mixture). A high voltage indicates a low contentof oxygen (rich mixture).

When the upstream O2S detects a lean condition,there is an abundance of oxygen in the exhaust gas.A functioning converter would store this oxygen so itcan use it for the oxidation of HC and CO. As theconverter absorbs the oxygen, there will be a lack ofoxygen downstream of the converter. The output ofthe downstream O2S will indicate limited activity inthis condition.

As the converter loses the ability to store oxygen,the condition can be detected from the behavior ofthe downstream O2S. When the efficiency drops, nochemical reaction takes place. This means the con-centration of oxygen will be the same downstream asupstream. The output voltage of the downstreamO2S copies the voltage of the upstream sensor. Theonly difference is a time lag (seen by the PCM)between the switching of the O2S’s.

To monitor the system, the number of lean-to-richswitches of upstream and downstream O2S’s iscounted. The ratio of downstream switches toupstream switches is used to determine whether thecatalyst is operating properly. An effective catalystwill have fewer downstream switches than it hasupstream switches i.e., a ratio closer to zero. For atotally ineffective catalyst, this ratio will be one-to-one, indicating that no oxidation occurs in the device.

The system must be monitored so that when cata-lyst efficiency deteriorates and exhaust emissionsincrease to over the legal limit, the MIL (CheckEngine lamp) will be illuminated.

LEAK DETECTION PUMP MONITORThe leak detection assembly incorporates two pri-

mary functions: it must detect a leak in the evapora-tive system and seal the evaporative system so theleak detection test can be run.

The primary components within the assembly are:A three port solenoid that activates both of the func-tions listed above; a pump which contains a switch,two check valves and a spring/diaphragm, a canistervent valve (CVV) seal which contains a spring loadedvent seal valve.

Immediately after a cold start, between predeter-mined temperature thresholds limits, the three portsolenoid is briefly energized. This initializes thepump by drawing air into the pump cavity and alsocloses the vent seal. During non test conditions the

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ent seal is held open by the pump diaphragmssembly which pushes it open at the full travel posi-ion. The vent seal will remain closed while theump is cycling due to the reed switch triggering ofhe three port solenoid that prevents the diaphragmssembly from reaching full travel. After the briefnitialization period, the solenoid is de-energizedllowing atmospheric pressure to enter the pumpavity, thus permitting the spring to drive the dia-hragm which forces air out of the pump cavity andnto the vent system. When the solenoid is energizednd de energized, the cycle is repeated creating flown typical diaphragm pump fashion. The pump is con-rolled in 2 modes:

Pump Mode: The pump is cycled at a fixed rate tochieve a rapid pressure build in order to shorten theverall test length.Test Mode: The solenoid is energized with a fixed

uration pulse. Subsequent fixed pulses occur whenhe diaphragm reaches the Switch closure point.

The spring in the pump is set so that the systemill achieve an equalized pressure of about 7.5” H20.he cycle rate of pump strokes is quite rapid as theystem begins to pump up to this pressure. As theressure increases, the cycle rate starts to drop off. Ifhere is no leak in the system, the pump would even-ually stop pumping at the equalized pressure. Ifhere is a leak, it will continue to pump at a rate rep-esentative of the flow characteristic of the size of theeak. From this information we can determine if theeak is larger than the required detection limit (cur-ently set at .040” orifice by CARB). If a leak isevealed during the leak test portion of the test, theest is terminated at the end of the test mode and nourther system checks will be performed.

After passing the leak detection phase of the test,ystem pressure is maintained by turning on theDP’s solenoid until the purge system is activated.urge activation in effect creates a leak. The cycleate is again interrogated and when it increases dueo the flow through the purge system, the leak checkortion of the diagnostic is complete.The canister vent valve will unseal the system

fter completion of the test sequence as the pumpiaphragm assembly moves to the full travel position.Evaporative system functionality will be verified by

sing the stricter evap purge flow monitor. At anppropriate warm idle the LDP will be energized toeal the canister vent. The purge flow will be clockedp from some small value in an attempt to see ahift in the 02 control system. If fuel vapor, indicatedy a shift in the 02 control, is present the test isassed. If not, it is assumed that the purge system isot functioning in some respect. The LDP is againurned off and the test is ended.

TRIP DEFINITION

OPERATIONA “Trip” means vehicle operation (following an

engine-off period) of duration and driving mode suchthat all components and systems are monitored atleast once by the diagnostic system. The monitorsmust successfully pass before the PCM can verifythat a previously malfunctioning component is meet-ing the normal operating conditions of that compo-nent. For misfire or fuel system malfunction, theMIL may be extinguished if the fault does not recurwhen monitored during three subsequent sequentialdriving cycles in which conditions are similar tothose under which the malfunction was first deter-mined.

Anytime the MIL is illuminated, a DTC is stored.The DTC can self erase only when the MIL has beenextinguished. Once the MIL is extinguished, thePCM must pass the diagnostic test for the mostrecent DTC for 40 warm-up cycles (80 warm-upcycles for the Fuel System Monitor and the MisfireMonitor). A warm-up cycle can best be described bythe following:

• The engine must be running• A rise of 40°F in engine temperature must occur

from the time when the engine was started• Engine coolant temperature must reach at least

160°F• A “driving cycle” that consists of engine start up

and engine shut off.Once the above conditions occur, the PCM is con-

sidered to have passed a warm-up cycle. Due to theconditions required to extinguish the MIL and erasethe DTC, it is most important that after a repair hasbeen made, all DTC’s be erased and the repair veri-fied.

MONITORED COMPONENT

DESCRIPTIONThere are several components that will affect vehi-

cle emissions if they malfunction. If one of these com-ponents malfunctions the Malfunction IndicatorLamp (Check Engine) will illuminate.

Some of the component monitors are checking forproper operation of the part. Electrically operatedcomponents now have input (rationality) and output(functionality) checks. Previously, a component likethe Throttle Position sensor (TPS) was checked bythe PCM for an open or shorted circuit. If one ofthese conditions occurred, a DTC was set. Now thereis a check to ensure that the component is working.This is done by watching for a TPS indication of agreater or lesser throttle opening than MAP andengine rpm indicate. In the case of the TPS, if engine

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acuum is high and engine rpm is 1600 or greaternd the TPS indicates a large throttle opening, aTC will be set. The same applies to low vacuumnd 1600 rpm.Any component that has an associated limp in will

et a fault after 1 trip with the malfunction present.Refer to the Diagnostic Trouble Codes Descriptionharts in this section and the appropriate Power-

rain Diagnostic Procedure Manual for diagnosticrocedures.The following is a list of the monitored compo-

ents:• Comprehensive Components• Oxygen Sensor Monitor• Oxygen Sensor Heater Monitor• Catalyst Monitor

OMPREHENSIVE COMPONENTSAlong with the major monitors, OBD II requires

hat the diagnostic system monitor any componenthat could affect emissions levels. In many cases,hese components were being tested under OBD I.he OBD I requirements focused mainly on testingmissions-related components for electrical opens andhorts.However, OBD II also requires that inputs from

owertrain components to the PCM be tested forationality, and that outputs to powertrain compo-ents from the PCM be tested for functionality.ethods for monitoring the various Comprehensiveomponent monitoring include:(1) Circuit Continuity• Open• Shorted high• Shorted to ground(2) Rationality or Proper Functioning• Inputs tested for rationality• Outputs tested for functionality

OTE: Comprehensive component monitors areontinuous. Therefore, enabling conditions do notpply.

Input Rationality— While input signals to theCM are constantly being monitored for electricalpens and shorts, they are also tested for rationality.his means that the input signal is compared againstther inputs and information to see if it makes sensender the current conditions.PCM sensor inputs that are checked for rationality

nclude:• Manifold Absolute Pressure (MAP) Sensor• Oxygen Sensor (O2S)• Engine Coolant Temperature (ECT) Sensor• Camshaft Position (CMP) Sensor• Vehicle Speed Sensor• Crankshaft Position (CKP) Sensor

• Intake Air Temperature (IAT) Sensor• Throttle Position (TPS) Sensor• Ambient/Battery Temperature Sensors• Power Steering Switch• Oxygen Sensor Heater• Engine Controller• Brake Switch• Leak Detection Pump Switch• P/N Switch• Trans ControlsOutput Functionality— PCM outputs are tested

for functionality in addition to testing for opens andshorts. When the PCM provides a voltage to an out-put component, it can verify that the command wascarried out by monitoring specific input signals forexpected changes. For example, when the PCM com-mands the Idle Air Control (IAC) Motor to a specificposition under certain operating conditions, it expectsto see a specific (target) idle speed (RPM). If it doesnot, it stores a DTC.

PCM outputs monitored for functionality include:• Fuel Injectors• Ignition Coils• Torque Converter Clutch Solenoid• Idle Air Control• Purge Solenoid• EGR Solenoid• LDP Solenoid• Radiator Fan Control• Trans Controls

OXYGEN SENSOR (O2S) MONITORDESCRIPTION— Effective control of exhaust

emissions is achieved by an oxygen feedback system.The most important element of the feedback systemis the O2S. The O2S is located in the exhaust path.Once it reaches operating temperature 300° to 350°C(572° to 662°F), the sensor generates a voltage thatis inversely proportional to the amount of oxygen inthe exhaust. When there is a large amount of oxygenin the exhaust caused by a lean condition, the sensorproduces a low voltage, below 450 mV. When the oxy-gen content is lower, caused by a rich condition, thesensor produces a higher voltage, above 450mV.

The information obtained by the sensor is used tocalculate the fuel injector pulse width. This main-tains a 14.7 to 1 air fuel (A/F) ratio. At this mixtureratio, the catalyst works best to remove hydrocarbons(HC), carbon monoxide (CO) and nitrous oxide (NOx)from the exhaust.

The O2S is also the main sensing element for theEGR, Catalyst and Fuel Monitors.

The O2S may fail in any or all of the followingmanners:

• Slow response rate (Big Slope)• Reduced output voltage (Half Cycle)

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• Heater PerformanceSlow Response Rate (Big Slope)— Response

ate is the time required for the sensor to switchrom lean to rich signal output once it is exposed to aicher than optimum A/F mixture or vice versa. Ashe PCM adjusts the air/fuel ratio, the sensor muste able to rapidly detect the change. As the sensorges, it could take longer to detect the changes in thexygen content of the exhaust gas. The rate ofhange that an oxygen sensor experiences is calledBig Slope’. The PCM checks the oxygen sensor volt-ge in increments of a few milliseconds.Reduced Output Voltage (Half Cycle)— The

utput voltage of the O2S ranges from 0 to 1 volt. Aood sensor can easily generate any output voltage inhis range as it is exposed to different concentrationsf oxygen. To detect a shift in the A/F mixture (leanr rich), the output voltage has to change beyond ahreshold value. A malfunctioning sensor could haveifficulty changing beyond the threshold value. Eachime the voltage signal surpasses the threshold, aounter is incremented by one. This is called the Halfycle Counter.Heater Performance— The heater is tested by a

eparate monitor. Refer to the Oxygen Sensor Heateronitor.OPERATION— As the Oxygen Sensor signal

witches, the PCM monitors the half cycle and biglope signals from the oxygen sensor. If during theest neither counter reaches a predetermined value, aalfunction is entered and a Freeze Frame is stored.nly one counter reaching its predetermined value iseeded for the monitor to pass.The Oxygen Sensor Monitor is a two trip monitor

hat is tested only once per trip. When the Oxygenensor fails the test in two consecutive trips, theIL is illuminated and a DTC is set. The MIL is

xtinguished when the Oxygen Sensor monitorasses in three consecutive trips. The DTC is erasedrom memory after 40 consecutive warm-up cyclesithout test failure.Enabling Conditions— The following conditionsust typically be met for the PCM to run the oxygen

ensor monitor:• Battery voltage• Engine temperature• Engine run time• Engine run time at a predetermined speed• Engine run time at a predetermined speed and

hrottle opening• Transmission in gear (automatic only)• Fuel system in Closed Loop• Long Term Adaptive (within parameters)• Power Steering Switch in low PSI (no load)• Engine at idle• Fuel level above 15%

• Ambient air temperature• Barometric pressure• Engine RPM within acceptable range of desired

idle• Closed throttle speedPending Conditions— The Task Manager typi-

cally does not run the Oxygen Sensor Monitor if over-lapping monitors are running or the MIL isilluminated for any of the following:

• Misfire Monitor• Front Oxygen Sensor and Heater Monitor• MAP Sensor• Vehicle Speed Sensor• Engine Coolant Temperature Sensor• Throttle Position Sensor• Engine Controller Self Test Faults• Cam or Crank Sensor• Injector and Coil• Idle Air Control Motor• EVAP Electrical• EGR Solenoid Electrical• Intake Air Temperature• 5 Volt FeedConflict— The Task Manager does not run the

Oxygen Sensor Monitor if any of the following condi-tions are present:

• A/C ON (A/C clutch cycling temporarily sus-pends monitor)

• Purge flow in progressSuspend— The Task Manager suspends maturing

a fault for the Oxygen Sensor Monitor if an of the fol-lowing are present:

• Oxygen Sensor Heater Monitor, Priority 1• Misfire Monitor, Priority 2

OXYGEN SENSOR HEATER MONITORDESCRIPTION— If there is an oxygen sensor

(O2S) DTC as well as a O2S heater DTC, the O2Sfault MUST be repaired first. After the O2S fault isrepaired, verify that the heater circuit is operatingcorrectly.

The voltage readings taken from the O2S are verytemperature sensitive. The readings are not accuratebelow 300°C. Heating of the O2S is done to allow theengine controller to shift to closed loop control assoon as possible. The heating element used to heatthe O2S must be tested to ensure that it is heatingthe sensor properly.

The heater element itself is not tested. The sensoroutput is used to test the heater by isolating theeffect of the heater element on the O2S output volt-age from the other effects. The resistance is normallybetween 100 ohms and 4.5 megaohms. When oxygensensor temperature increases, the resistance in theinternal circuit decreases. The PCM sends a 5 voltsbiased signal through the oxygen sensors to ground

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his monitoring circuit. As the temperature increases,esistance decreases and the PCM detects a loweroltage at the reference signal. Inversely, as the tem-erature decreases, the resistance increases and theCM detects a higher voltage at the reference signal.n The O2S circuit is monitored for a drop in voltage.OPERATION— The Oxygen Sensor Heater Moni-

or begins after the ignition has been turned OFFnd the O2 sensors have cooled. The PCM sends a 5olt bias to the oxygen sensor every 1.6 seconds. TheCM keeps it biased for 35 ms each time. As the sen-or cools down, the resistance increases and the PCMeads the increase in voltage. Once voltage hasncreased to a predetermined amount, higher thanhen the test started, the oxygen sensor is coolnough to test heater operation.When the oxygen sensor is cool enough, the PCM

nergizes the ASD relay. Voltage to the O2 sensoregins to increase the temperature. As the sensoremperature increases, the internal resistanceecreases. The PCM continues biasing the 5 volt sig-al to the sensor. Each time the signal is biased, theCM reads a voltage decrease. When the PCMetects a voltage decrease of a predetermined valueor several biased pulses, the test passes.

The heater elements are tested each time thengine is turned OFF if all the enabling conditionsre met. If the monitor fails, the PCM stores aaturing fault and a Freeze Frame is entered. If two

onsecutive tests fail, a DTC is stored. Because thegnition is OFF, the MIL is illuminated at the begin-ing of the next key cycle.Enabling Conditions— The following conditionsust be met for the PCM to run the oxygen sensoreater test:• Engine run time of at least 5.1 minutes• Key OFF power down• Battery voltage of at least 10 volts• Sufficient Oxygen Sensor cool downPending Conditions— There are not conditions

r situations that prompt conflict or suspension ofesting. The oxygen sensor heater test is not runending resolution of MIL illumination due to oxygenensor failure.Suspend— There are no conditions which exist for

uspending the Heater Monitor.

ATALYST MONITORTo comply with clean air regulations, vehicles are

quipped with catalytic converters. These converterseduce the emission of hydrocarbons, oxides of nitro-en and carbon monoxide.Normal vehicle miles or engine misfire can cause a

atalyst to decay. A meltdown of the ceramic core canause a reduction of the exhaust passage. This can

increase vehicle emissions and deteriorate engineperformance, driveability and fuel economy.

The catalyst monitor uses dual oxygen sensors(O2S’s) to monitor the efficiency of the converter. Thedual O2S strategy is based on the fact that as a cat-alyst deteriorates, its oxygen storage capacity and itsefficiency are both reduced. By monitoring the oxy-gen storage capacity of a catalyst, its efficiency canbe indirectly calculated. The upstream O2S is used todetect the amount of oxygen in the exhaust gasbefore the gas enters the catalytic converter. ThePCM calculates the A/F mixture from the output ofthe O2S. A low voltage indicates high oxygen content(lean mixture). A high voltage indicates a low contentof oxygen (rich mixture).

When the upstream O2S detects a lean condition,there is an abundance of oxygen in the exhaust gas.A functioning converter would store this oxygen so itcan use it for the oxidation of HC and CO. As theconverter absorbs the oxygen, there will be a lack ofoxygen downstream of the converter. The output ofthe downstream O2S will indicate limited activity inthis condition.

As the converter loses the ability to store oxygen,the condition can be detected from the behavior ofthe downstream O2S. When the efficiency drops, nochemical reaction takes place. This means the con-centration of oxygen will be the same downstream asupstream. The output voltage of the downstreamO2S copies the voltage of the upstream sensor. Theonly difference is a time lag (seen by the PCM)between the switching of the O2S’s.

To monitor the system, the number of lean-to-richswitches of upstream and downstream O2S’s iscounted. The ratio of downstream switches toupstream switches is used to determine whether thecatalyst is operating properly. An effective catalystwill have fewer downstream switches than it hasupstream switches i.e., a ratio closer to zero. For atotally ineffective catalyst, this ratio will be one-to-one, indicating that no oxidation occurs in the device.

The system must be monitored so that when cata-lyst efficiency deteriorates and exhaust emissionsincrease to over the legal limit, the MIL (checkengine lamp) will be illuminated.

Monitor Operation— To monitor catalyst effi-ciency, the PCM expands the rich and lean switchpoints of the heated oxygen sensor. With extendedswitch points, the air/fuel mixture runs richer andleaner to overburden the catalytic converter. Oncethe test is started, the air/fuel mixture runs rich andlean and the O2 switches are counted. A switch iscounted when an oxygen sensor signal goes frombelow the lean threshold to above the rich threshold.The number of Rear O2 sensor switches is divided by

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The test runs for 20 seconds. As catalyst efficiencyeteriorated over the life of the vehicle, the switchate at the downstream sensor approaches that of thepstream sensor. If at any point during the testeriod the switch ratio reaches a predeterminedalue, a counter is incremented by one. The monitors enabled to run another test during that trip. Whenhe test fails three times, the counter increments tohree, a malfunction is entered, and a Freeze Frames stored. When the counter increments to three dur-ng the next trip, the code is matured and the MIL islluminated. If the test passes the first, no furtheresting is conducted during that trip.

The MIL is extinguished after three consecutiveood trips. The good trip criteria for the catalystonitor is more stringent than the failure criteria. In

rder to pass the test and increment one good trip,he downstream sensor switch rate must be less than0% of the upstream rate (60% for manual transmis-ions). The failure percentages are 90% and 70%espectively.Enabling Conditions— The following conditionsust typically be met before the PCM runs the cat-

lyst monitor. Specific times for each parameter maye different from engine to engine.• Accumulated drive time• Enable time• Ambient air temperature• Barometric pressure• Catalyst warm-up counter• Engine coolant temperature• Accumulated throttle position sensor• Vehicle speed• MAP• RPM• Engine in closed loop• Fuel levelPending Conditions—• Misfire DTC• Front Oxygen Sensor Response• Front Oxygen Sensor Heater Monitor• Front Oxygen Sensor Electrical• Rear Oxygen Sensor Rationality (middle check)• Rear Oxygen Sensor Heater Monitor• Rear Oxygen Sensor Electrical• Fuel System Monitor• All TPS faults• All MAP faults• All ECT sensor faults• Purge flow solenoid functionality• Purge flow solenoid electrical• All PCM self test faults• All CMP and CKP sensor faults• All injector and ignition electrical faults

• Idle Air Control (IAC) motor functionality• Vehicle Speed Sensor• Brake switch• Intake air temperatureConflict— The catalyst monitor does not run if

any of the following are conditions are present:• EGR Monitor in progress• Fuel system rich intrusive test in progress• EVAP Monitor in progress• Time since start is less than 60 seconds• Low fuel level• Low ambient air temperatureSuspend— The Task Manager does not mature a

catalyst fault if any of the following are present:• Oxygen Sensor Monitor, Priority 1• Upstream Oxygen Sensor Heater, Priority 1• EGR Monitor, Priority 1• EVAP Monitor, Priority 1• Fuel System Monitor, Priority 2• Misfire Monitor, Priority 2

NON-MONITORED CIRCUITS

OPERATIONThe PCM does not monitor all circuits, systems

and conditions that could have malfunctions causingdriveability problems. However, problems with thesesystems may cause the PCM to store diagnostic trou-ble codes for other systems or components. For exam-ple, a fuel pressure problem will not register a faultdirectly, but could cause a rich/lean condition or mis-fire. This could cause the PCM to store an oxygensensor or misfire diagnostic trouble code.

The major non-monitored circuits are listed belowalong with examples of failures modes that do notdirectly cause the PCM to set a DTC, but for a sys-tem that is monitored.

FUEL PRESSUREThe fuel pressure regulator controls fuel system

pressure. The PCM cannot detect a clogged fuelpump inlet filter, clogged in-line fuel filter, or apinched fuel supply or return line. However, thesecould result in a rich or lean condition causing thePCM to store an oxygen sensor or fuel system diag-nostic trouble code.

SECONDARY IGNITION CIRCUITThe PCM cannot detect an inoperative ignition coil,

fouled or worn spark plugs, ignition cross firing, oropen spark plug cables.

CYLINDER COMPRESSIONThe PCM cannot detect uneven, low, or high engine

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XHAUST SYSTEMThe PCM cannot detect a plugged, restricted or

eaking exhaust system. It may set a EGR or Fuelystem fault or O2S.

UEL INJECTOR MECHANICAL MALFUNCTIONSThe PCM cannot determine if a fuel injector is

logged, the needle is sticking or if the wrong injectors installed. However, these could result in a rich orean condition causing the PCM to store a diagnosticrouble code for either misfire, an oxygen sensor, orhe fuel system.

XCESSIVE OIL CONSUMPTIONAlthough the PCM monitors engine exhaust oxygen

ontent when the system is in closed loop, it cannotetermine excessive oil consumption.

HROTTLE BODY AIR FLOWThe PCM cannot detect a clogged or restricted air

leaner inlet or filter element.

ACUUM ASSISTThe PCM cannot detect leaks or restrictions in the

acuum circuits of vacuum assisted engine controlystem devices. However, these could cause the PCMo store a MAP sensor diagnostic trouble code andause a high idle condition.

PCM SYSTEM GROUNDThe PCM cannot determine a poor system ground.

However, one or more diagnostic trouble codes maybe generated as a result of this condition. The mod-ule should be mounted to the body at all times, alsoduring diagnostic.

PCM CONNECTOR ENGAGEMENTThe PCM may not be able to determine spread or

damaged connector pins. However, it might storediagnostic trouble codes as a result of spread connec-tor pins.

HIGH AND LOW LIMITS

OPERATIONThe PCM compares input signal voltages from each

input device with established high and low limits forthe device. If the input voltage is not within limitsand other criteria are met, the PCM stores a diagnos-tic trouble code in memory. Other diagnostic troublecode criteria might include engine RPM limits orinput voltages from other sensors or switches thatmust be present before verifying a diagnostic troublecode condition.

PECIFICATIONS

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3.5L 1% to 8%

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EVAPORATIVE EMISSION CONTROLS

TABLE OF CONTENTS

page page

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ESCRIPTION AND OPERATIONEVAPORATION CONTROL SYSTEM . . . . . . . . . . 20EVAP CANISTER . . . . . . . . . . . . . . . . . . . . . . . . . 20PROPORTIONAL PURGE SOLENOID—PCM

OUTPUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20LEAK DETECTION PUMP . . . . . . . . . . . . . . . . . . 21LEAK DETECTION PUMP PRESSURE

SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22POSITIVE CRANKCASE VENTILATION (PCV)

SYSTEMS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

POSITIVE CRANKCASE VENTILATION VALVE. . . 23VEHICLE EMISSION CONTROL

INFORMATION LABEL . . . . . . . . . . . . . . . . . . . 24IAGNOSIS AND TESTINGPCV SYSTEM INSPECTION. . . . . . . . . . . . . . . . . 24LEAK DETECTION PUMP . . . . . . . . . . . . . . . . . . 25EMOVAL AND INSTALLATIONEVAP CANISTER . . . . . . . . . . . . . . . . . . . . . . . . . 25LEAK DETECTION PUMP . . . . . . . . . . . . . . . . . . 26
PROPORTIONAL PURGE SOLENOID VALVE . . . . 26

VAPORATION CONTROL SYSTEM

PERATIONThe evaporation control system prevents the emis-

ion of fuel tank vapors into the atmosphere. Whenuel evaporates in the fuel tank, the vapors passhrough vent hoses or tubes to an activated carbonilled evaporative canister. The canister temporarilyolds the vapors. The Powertrain Control ModulePCM) allows intake manifold vacuum to drawapors into the combustion chambers during certainperating conditions (Fig. 1).All engines use a proportional purge solenoid sys-

em. The PCM controls vapor flow by operating theurge solenoid. Refer to Proportional Purge Solenoidn this section.

OTE: The evaporative system uses specially man-factured hoses. If they need replacement, only use

uel resistant hose. Also the hoses must be able toass an Ozone compliance test.

OTE: For more information on Onboard Refuelingapor Recovery (ORVR), refer to the Fuel Deliveryection.

EVAP CANISTER

DESCRIPTIONThe canister protrudes through the top of the

bracket. The vacuum and vapor tubes connect to thetop of the canister (Fig. 2). It is a charcoal canister.

OPERATIONAll vehicles use a, maintenance free, evaporative

(EVAP) canister. Fuel tank vapors vent into the can-ister. The canister temporarily holds the fuel vaporsuntil intake manifold vacuum draws them into thecombustion chamber. The Powertrain Control Module(PCM) purges the canister through the proportionalpurge solenoid. The PCM purges the canister at pre-determined intervals and engine conditions.

PROPORTIONAL PURGE SOLENOID—PCMOUTPUT

DESCRIPTIONAll vehicles use a proportional purge solenoid. The

solenoid regulates the rate of vapor flow from theEVAP canister to the throttle body. The PCM oper-ates the solenoid.



OPERATIONDuring the cold start warm-up period and the hot

start time delay, the PCM does not energize the sole-noid. When de-energized, no vapors are purged.

The proportional purge solenoid operates at a fre-quency of 200 hz and is controlled by an engine con-troller circuit that senses the current being appliedto the proportional purge solenoid (Fig. 3) and thenadjusts that current to achieve the desired purgeflow. The proportional purge solenoid controls thepurge rate of fuel vapors from the vapor canister andfuel tank to the engine intake manifold.

LEAK DETECTION PUMP

DESCRIPTIONThe leak detection pump is a device used to detect

a leak in the evaporative system.The pump contains a 3 port solenoid, a pump that

contains a switch, a spring loaded canister vent valveseal, 2 check valves and a spring/diaphragm.

m Schematic7 – BREATHER ELEMENT8 – W/0 LDP9 – CANISTER10 – ROLLOVER VALVE11 – FUEL TANK12 – CHECK VALVE

Fig. 1 ORVR Syste1 – FUEL CAP2 – RECIRCULATION TUBE3 – CONTROL VALVE4 – FLOW MANAGEMENT VALVE5 – PURGE6 – W/LDP

Fig. 2 EVAP Canister1 – EVAP CANISTER2 – EVAP CANISTER BRACKET

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PERATIONImmediately after a cold start, when the engine

emperature is between 40°F and 86°F, the 3 portolenoid is briefly energized. This initializes theump by drawing air into the pump cavity and alsoloses the vent seal. During non-test test conditions,he vent seal is held open by the pump diaphragmssembly which pushes it open at the full travel posi-ion. The vent seal will remain closed while theump is cycling. This is due to the operation of the 3ort solenoid which prevents the diaphragm assem-ly from reaching full travel. After the brief initial-zation period, the solenoid is de-energized, allowingtmospheric pressure to enter the pump cavity. Thisermits the spring to drive the diaphragm whichorces air out of the pump cavity and into the ventystem. When the solenoid is energized and de-ener-ized, the cycle is repeated creating flow in typicaliaphragm pump fashion. The pump is controlled inmodes:PUMP MODE: The pump is cycled at a fixed rate

o achieve a rapid pressure build in order to shortenhe overall test time.

TEST MODE: The solenoid is energized with aixed duration pulse. Subsequent fixed pulses occurhen the diaphragm reaches the switch closureoint.The spring in the pump is set so that the systemill achieve an equalized pressure of about 7.5 inchesf water.When the pump starts, the cycle rate is quite high.s the system becomes pressurized, pump rate drops.

f there is no leak, the pump will quit. If there is a

Fig. 3 Proportional Purge Solenoid1 – PROPORTIONAL PURGE SOLENOID2 – O2 SENSOR

leak, the test is terminated at the end of the testmode.

If there is no leak, the purge monitor is run. If thecycle rate increases due to the flow through thepurge system, the test is passed and the diagnostic iscomplete.

The canister vent valve will unseal the systemafter completion of the test sequence as the pumpdiaphragm assembly moves to the full travel position.

LEAK DETECTION PUMP PRESSURE SWITCH

DESCRIPTIONThe primary components within the leak detection

pump assembly are: a three-port leak detection sole-noid valve, a pump assembly that includes a springloaded diaphragm, a reed switch which is used tomonitor the pump diaphragm movement (position),two check valves, and a spring loaded vent sealvalve.

OPERATIONThe leak detection pump LDP assembly incorpo-

rates two primary functions: it detects a leak in theevaporative system, and it seals the evaporative sys-tem so that the required leak detection monitor testcan be run.

The three-port LDP solenoid valve is used toexpose either engine vacuum or atmospheric pressureto the top side of the leak detection pump diaphragm.

When the LDP solenoid valve is deenergized itsport (opening) to engine vacuum is blocked off. Thisallows ambient air (atmospheric pressure) to enterthe top of the pump diaphragm. The spring load onthe diaphragm will push the diaphragm down, aslong as there is no pressure present in the rest of theevaporative system. If there is sufficient evaporativesystem pressure present, then the pump diaphragmwill stay in the “up” position. If the evaporative sys-tem pressure decays, then the pump diaphragm willeventually fall. The rate of this decent is dependentupon the size of the evaporative system leak (Largeor small).

When the LDP solenoid valve is energized the port(opening) to atmosphere is blocked off. At the sametime, the port to engine vacuum is opened. Enginevacuum replaces atmospheric pressure. When enginevacuum is sufficient, it over comes the spring pres-sure load on the pump diaphragm and causes thediaphragm to rise to its “up” position. The reedswitch will change state depending upon the positionof the pump diaphragm.

If the diaphragm is in the “up” position the reedswitch will be in its “open” state. This means thatthe 12 volt signal sense to the PCM is interrupted.Zero volts is detected by the PCM. If the pump dia-

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DESCRIPTION AND OPERATION (Continued)2000 LHS, 300M, CONCORDE and INTREPIDPublication No. 81-270-0040TSB 26-10-99 October, 1999

hragm is in the “down” position the reed switch wille in its “closed” state. 12 volts is sent to the PCMia the switch sense circuit.The check valves are one-way valves. The first

heck valve is used to draw outside air into the lowerhamber of the LDP (the space that is below theump diaphragm). The second check valve is used toent this outside air, which has become pressurizedrom the fall of the pump diaphragm, into the evap-rative system.The spring loaded vent seal valve, inside the LDP

s used to seal off the evaporative system. When theump diaphragm is in the “up” position the springushes the vent seal valve closed. The vent seal valvepens only when the pump diaphragm is in its “fullown” position. When the pump assembly is in itsump mode the pump diaphragm is not allowed toescend (fall) so far as to allow the vent seal valve topen. This allows the leak detection pump to develophe required pressure within the evaporative systemor system leak testing.

A pressure build up within the evaporative systemay cause pressure on the lower side of the LDP dia-

hragm. This will cause the LDP diaphragm toemain in its “up” position (stuck in the up position).his condition can occur even when the solenoidalve is deenergized. This condition can be caused byrevious cycling (pumping) of the LDP by the techni-ian (dealer test). Another way that this condition isreated is immediately following the running of theehicle evaporative system monitor. In this case, theCM has not yet opened the proportional purge sole-oid in order to vent the pressure that has been builtp in the evaporative system to the engine combus-ion system. The technician will need to vent thevaporative system pressure via the vehicle fuel fillerap and its fuel filler secondary seal (if so equippedn the fuel filler neck). This will allow the techniciano cycle the LDP and to watch switch state changes.

After passing the leak detection phase of the test,ystem pressure is maintained until the purge sys-em is activated, in effect creating a leak. If the dia-hragm falls (as is expected), causing the reed switcho change state, then the diagnostic test is completed.

When of the evaporative system leak monitoregins its various tests, a test is performed to deter-ine that no part of the evaporative system is

locked. In this test, the LDP is cycled (pumped) aalibrated (few) number of times. Pressure should notuild up in the evaporative system. If pressure isresent, then LDP diaphragm is forced to stay in itsup” position. The reed switch now stays open andhe PCM senses this open (incorrect) state. The evap-rative system monitor will fail the test because of aetected obstruction within the system.

Possible causes:• Open or shorted LDP switch sense circuit• Leak Detection Pump switch failure• Open fused ignition switch output• Restricted, disconnected, or blocked manifold

vacuum source• Obstruction of hoses or lines• PCM failure

POSITIVE CRANKCASE VENTILATION (PCV)SYSTEMS

OPERATIONIntake manifold vacuum removes crankcase vapors

and piston blow-by from the engine. Emissions passthrough the PCV valve into the intake manifold ple-num (Fig. 4) or (Fig. 5). The vapors become part ofthe calibrated air-fuel mixture, are burned andexpelled with the exhaust gases. The air cleaner sup-plies make up air when the engine does not haveenough vapor or blow-by gases.

It has a heat exchange system to help improve coldweather operation.

POSITIVE CRANKCASE VENTILATION VALVE

OPERATIONThe PCV valve contains a spring loaded plunger.

The plunger meters the amount of crankcase vaporsrouted into the combustion chamber based on intakemanifold vacuum.

Fig. 4 PCV Valve—2.7L Engine1 – PCV VALVE

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DESCRIPTION AND OPERATION (Continued)2000 LHS, 300M, CONCORDE and INTREPIDPublication No. 81-270-0040TSB 26-10-99 October, 1999

When the engine is not operating or during anngine backfire, the spring forces the plunger backgainst the seat. This prevents vapors from flowinghrough the valve (Fig. 6).

When the engine is at idle or cruising, high mani-old vacuum is present. At these times manifold vac-um is able to completely compress the spring andull the plunger to the top of the valve (Fig. 7). Inhis position there is minimal vapor flow through thealve.

Fig. 5 PCV Valve—3.2/3.5L Engine1 – PCV VALVE

Fig. 6 Engine Off or Engine Backfire—No VaporFlow

Fig. 7 High Intake Manifold Vacuum—Minimal VaporFlow

During periods of moderate intake manifold vac-uum the plunger is only pulled part way back fromthe inlet. This results in maximum vapor flowthrough the valve (Fig. 8).

VEHICLE EMISSION CONTROL INFORMATIONLABEL

DESCRIPTIONAll models have a Vehicle Emission Control Infor-

mation (VECI) Label. Chrysler permanently attachesthe label in the engine compartment. It cannot beremoved without defacing information and destroyingthe label.

The label contains the vehicle’s emission specifica-tions and vacuum hose routings. All hoses must beconnected and routed according to the label.

DIAGNOSIS AND TESTING

PCV SYSTEM INSPECTION

WARNING: APPLY PARKING BRAKE AND/ORBLOCK WHEELS BEFORE PERFORMING ANY TESTOR ADJUSTMENT WITH THE ENGINE OPERATING.

(1) With engine idling, remove the hose from thePCV valve. If the valve is not plugged, a hissingnoise will be heard as air passes through the valve. Astrong vacuum should also be felt when a finger isplaced over the valve inlet.

(2) Install hose on PCV valve. Remove themake-up air hose from the air plenum at the rear ofthe engine. Hold a piece of stiff paper (parts tag)loosely over the end of the make-up air hose.

(3) After allowing approximately one minute forcrankcase pressure to reduce, the paper should drawup against the hose with noticeable force. If theengine does not draw the paper against the grommetafter installing a new valve, replace the PCV valvehose.

(4) Turn the engine off. Remove the PCV valvefrom intake manifold. The valve should rattle whenshaken.

Fig. 8 Moderate Intake Manifold Vacuum—MaximumVapor Flow

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DIAGNOSIS AND TESTING (Continued)

(5) Replace the PCV valve and retest the system ift does not operate as described in the precedingests. Do not attempt to clean the old PCV valve.f the valve rattles, apply a light coating of Loctitetipe Sealant With Teflon to the threads. Thread theCV valve into the manifold plenum and tighten to 7·m (60 in. lbs.) torque.

EAK DETECTION PUMPRefer to the appropriate Powertrain Diagnostic

rocedures Manual for testing procedures.

EMOVAL AND INSTALLATION

VAP CANISTER

EMOVAL(1) Disconnect the negative battery cable.(2) Remove fuel tank refer to the Fuel Delivery

ection.(3) Disconnect the hoses from the EVAP canister

Fig. 9).

(4) Remove 2 nuts from the upper bracket of theVAP canister (Fig. 10).

Fig. 9 EVAP Canister and LDP

(5) Remove EVAP canister from bracket (Fig. 12).

(6) Remove LDP from EVAP canister upperbracket (Fig. 13).

INSTALLATION(1) Install LDP to EVAP Canister. (Fig. 13).(2) Install EVAP canister to Bracket (Fig. 12).(3) Install 2 nuts to EVAP canister bracket.(4) Connect hoses.

Fig. 10 EVAP Bracket1 – NUTS2 – LDP MOUNTING SCREWS3 – LDP

Fig. 11 EVAP Mounting Grommets1 – RUBBER MOUNTING GROMMETS

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REMOVAL AND INSTALLATION (Continued)

(5) Install fuel tank refer to the Fuel Delivery sec-ion.

(6) Connect negative battery cable.

EAK DETECTION PUMP

EMOVAL(1) Disconnect the negative battery cable.(2) Remove fuel tank refer to Group 14, Fuelelivery.

Fig. 12 EVAP Canister Bracket1 – EVAP CANISTER2 – EVAP CANISTER BRACKET

Fig. 13 LDP Mounting Screws1 – LDP2 – LDP MOUNTING SCREWS

(3) Disconnect the hoses from the EVAP canister(Fig. 9).

(4) Remove 2 nuts from the upper bracket of theEVAP canister (Fig. 10).

(5) Remove EVAP canister from bracket (Fig. 12).(6) Remove LDP from EVAP canister upper

bracket (Fig. 13).

INSTALLATION(1) Install LDP to EVAP Canister. (Fig. 13).(2) Install EVAP canister to Bracket (Fig. 12).(3) Install 2 nuts to EVAP canister bracket.(4) Connect hoses.(5) Install fuel tank refer to Group 14, Fuel Deliv-

ery.(6) Connect negative battery cable.

PROPORTIONAL PURGE SOLENOID VALVEThe solenoid attaches to a bracket near the air

cleaner (Fig. 14). The solenoid will not operate unlessit is installed correctly.

REMOVAL(1) Disconnect electrical connector from solenoid.(2) Disconnect vacuum tubes from solenoid.(3) Remove solenoid from bracket.

INSTALLATIONThe top of the solenoid has TOP printed on it. The

solenoid will not operate unless it is installed cor-rectly.

(1) Install solenoid on bracket.(2) Connect vacuum tube to solenoid.(3) Connect electrical connector to solenoid.

Fig. 14 Proportional Purge Solenoid Valve1 – PROPORTIONAL PURGE SOLENOID2 – O2 SENSOR

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EXHAUST GAS RECIRCULATION (EGR) SYSTEM

TABLE OF CONTENTS

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S

ESCRIPTION AND OPERATIONEXHAUST GAS RECIRCULATION (LSEGR) . . . . . 27EMOVAL AND INSTALLATIONEGR VALVE—2.7L . . . . . . . . . . . . . . . . . . . . . . . . 27
EGR VALVE—3.2/3.5L . . . . . . . . . . . . . . . . . . . . . 27
EGR TUBE UPPER—2.7L . . . . . . . . . . . . . . . . . . 28EGR TUBE LOWER—2.7L . . . . . . . . . . . . . . . . . . 29EGR TUBE—3.2/3.5L . . . . . . . . . . . . . . . . . . . . . . 29PECIFICATIONS
TORQUE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

XHAUST GAS RECIRCULATION (LSEGR)

ESCRIPTIONThe EGR valve consists of three major components.

irst there is the pintle, valve seat, and housinghich contains and regulates the gas flow. Second

here is the armature, return spring, and solenoidoil to provide the operating force to regulate thelow by changing the pintle position. The solenoid coilssembly is in parallel with a diode and connects tohe two connectors in the connector assembly. Thehird major component which senses pintle positionnd is connected to the three connectors in the elec-rical connector.

PERATIONThe exhaust gas recirculation flow is determined

y the engine controller. For a given set of conditions,he engine controller knows the ideal exhaust gasecirculation flow to optimize NOx and fuel economys a function of the pintle position. Pintle position isbtained from the position sensor. The engine con-roller adjusts the duty cycle of 128 Hz power sup-lied to the solenoid coil to obtain the correctosition.

EMOVAL AND INSTALLATION

GR VALVE—2.7L

EMOVALThe EGR valve attaches to the rear of the right

ylinder head.(1) Disconnect negative battery cable.(2) Remove air inlet tube and resonator and

racket.(3) Disconnect electrical connector from solenoid.(4) Remove EGR upper tube screws at EGR valve.(5) Remove EGR valve mounting screws.

(6) Remove screws from EGR lower tube atexhaust manifold.

(7) Remove EGR valve and lower tube as anassembly.

(8) Clean gasket surfaces. Discard old gasket. Ifnecessary, clean EGR passages.

INSTALLATION(1) Loosely install EGR valve and lower tube, use

a new gasket between tube and EGR valve.(2) Install EGR valve to rear of Cylinder head, do

not tighten screws.(3) Loosely install screws to lower EGR tube to

exhaust manifold, use new gasket between tube andexhaust manifold.

(4) Install new gasket between the EGR valve andupper tube and install bolts.

(5) Tighten EGR lower tube to exhaust manifoldscrews to 31 N·m (275 in. lbs.) torque.

(6) Tighten the EGR tube’s to EGR valve bolts to11 N·m (95 in. lbs.) torque.

(7) Tighten EGR valve to cylinder head screws to31 N·m (275 in. lbs.) torque.

(8) Attach electrical connector to solenoid.(9) Install the resonator bracket.(10) Install air inlet tube and resonator.(11) Connect negative battery cable.

EGR VALVE—3.2/3.5L

REMOVAL(1) Disconnect negative battery cable.(2) Remove air inlet tube and resonator.(3) Disconnect electrical connector from EGR

valve.(4) Remove EGR tube mounting screws at EGR

valve.The EGR valve attaches to the rear of the right

cylinder head.(5) Remove EGR valve mounting screws.(6) Clean gasket surfaces. Discard old gasket. If

necessary, clean EGR passages.

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NSTALLATION(1) Loosely install EGR valve and new gasket on

ylinder head.(2) Using a new gasket, loosely install the EGR

ube and mounting screws..(3) Tighten EGR valve to cylinder head screws to

1 N·m (275 in. lbs.) torque.(4) Tighten the EGR tube to EGR valve screws to

1 N·m (95 in. lbs.) torque.(5) Attach electrical connector to solenoid.(6) Install air inlet tube and resonator.(7) Connect negative battery cable.

Fig. 1 EGR Valve—2.7 L

Fig. 2 EGR tube and Valve1 – EGR TUBE2 – EGR VALVE

EGR TUBE UPPER—2.7LThe EGR tube attaches to the intake manifold ple-

num on both sides of the throttle body and the EGRvalve.

REMOVAL(1) Disconnect negative battery cable.(2) Remove air inlet tube and resonator.(3) Remove throttle cable bracket and reposition.(4) Remove EGR tube mounting screws at intake

manifold plenum (Fig. 4).

(5) Remove EGR tube mounting screws at EGRvalve.

(6) Remove EGR upper tube.

Fig. 3 EGR Tube—2.7L

Fig. 4 EGR Tube at Intake Manifold1 – PCV VALVE2 – THROTTLE BODY3 – EGR TUBE

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(7) When removing EGR upper tube assembly beingareful not to drop the silicone rubber seals in thentake manifold. Clean gasket surfaces on the EGRalve. Note that any loose dirt can lodge between theintle and the seat and cause valve leakage that willive a rough idle and depressed manifold vacuum.

NSTALLATION(1) inspect rubber silicone seals on intake manifold

nd of EGR tube.(2) Install upper tube into the intake manifold,

eing careful that the silicone rubber seals are cor-ectly installed and undamaged..(3) Install new gasket between the EGR valve and

ube and install bolts.(4) Tighten the EGR upper tube to intake manifold

lenum screws to 11 N·m (95 in. lbs.) torque.(5) Tighten the EGR upper tube to EGR valve

olts to 11 N·m (95 in. lbs.) torque.(6) Install the throttle cable bracket to intakeanifold.(7) Install air inlet tube and resonator.(8) Connect negative battery cable.

GR TUBE LOWER—2.7L

EMOVAL(1) Disconnect negative battery cable.(2) Remove air inlet tube and resonator and

racket

Fig. 5 EGR Tube at Intake Manifold1 – EGR TUBE2 – IGNITION COILS3 – EGR TUBE4 – MAKE UP AIR TUBE

(3) Remove EGR tube mounting screws at EGRvalve (Fig. 5).

(4) Remove EGR tube mounting screws at exhaustmanifold.

INSTALLATION(1) Install new gasket between the EGR valve and

tube and loosely install bolts.(2) Install new gasket between the exhaust mani-

fold and tube and loosely install bolts.(3) Tighten the EGR tube to EGR valve bolts to 11

N·m (95 in. lbs.) torque.(4) Tighten the EGR tube to exhaust manifold

bolts to 31 N·m (275 in. lbs.) torque.(5) Install air inlet tube and resonator and

bracket.(6) Connect negative battery cable.

EGR TUBE—3.2/3.5LThe EGR tube attaches to the bottom of the intake

manifold plenum beside the throttle body (Fig. 7).

REMOVAL(1) Disconnect negative battery cable.(2) Remove air inlet tube and resonator.(3) Remove EGR tube mounting clips at intake

manifold plenum (Fig. 6).

(4) Loosen transmission to throttle body bracket(Fig. 7). Remove 2 nuts and 1 bolt and removebracket off of studs.

(5) Remove EGR tube mounting screws at EGRvalve.

Fig. 6 EGR Tube Clips1 – EGR VALVE2 – EGR TUBE3 – CLIP

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When removing EGR upper tube assembly beingareful not to drop the silicone rubber seals in thentake manifold. Clean gasket surfaces on the EGRalve. Note that any loose dirt can lodge between theintle and the seat and cause valve leakage that willive a rough idle and depressed manifold vacuum.(6) Remove EGR tube.

NSTALLATION(1) Install rubber silicone seals on intake manifold

nd of EGR tube (Fig. 8), being careful to be sure sil-cone rubber seals is correctly installed and undam-ged.(2) Using a new gasket, loosely install the EGR

ube into the intake manifold and loosely install EGRube to EGR valve.

(3) Tighten the EGR tube to EGR valve screws to1 N·m (95 in. lbs.) torque.(4) Install clips for the EGR tube to intake mani-

old plenum (Fig. 9).(5) Install transmission to throttle body bracket.(6) Install air inlet tube and resonator.(7) Connect negative battery cable.

Fig. 7 Bracket and EGR Tube1 – EGR TUBE2 – BRACKET3 – EGR VALVE

SPECIFICATIONS

TORQUE

Description TorqueEGR valve to cyl. head . . . . . . 31 N·m (275 in. lbs.)EGR tube to EGR valve . . . . . . 11 N·m (95 in. lbs.)EGR tube to intake manifold . . 11 N·m (95 in. lbs.)EGR tube to exhaust manifold . . . . . . . . . . 31 N·m

(275 in. lbs.)

Fig. 8 EGR tube Seal1 – SILICONE SEAL

Fig. 9 EGR Tube and Clip

emission control systems - dodge intrepid

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