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13A FUEL MPI 1999 – General/General Information/Troubleshooting
MULTIPOINT FUEL INJECTION (MPI) <4G1>GENERALOUTLINE OF CHANGE� 4G15 engines have been added in vehicles for New Zealand. Service procedures are basically the
same as the conventional 4G15 engines in vehicles for Australia.� The diagnosis connector power supply circuit has been changed in 4G15 engines for Australia and
New Zealand.� The engine-ECU has been changed to correspond to the addition of stronger exhaust gas purification
measures in vehicles with 4G15 engine for Australia.
GENERAL INFORMATIONGENERAL SPECIFICATIONS
Items Specifications
Engine-ECU Identification No. E2T69285 <Vehicles with strengthened exhaustgas purification measures>
TROUBLESHOOTINGINSPECTION CHART FOR TROUBLE SYMPTOM
Trouble symptom InspectionprocedureNo.
Referencepage
Communication with MUT-II is impossi-ble
Communication with all systems is notpossible.
1 See below
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMINSPECTION PROCEDURE 1
Communication with MUT-II is not possible.(Communication with all system is not possible.)
Probable cause
The cause is probably a defect in the power supply system (including earth) for thediagnosis line.
� Malfunction of the connector� Malfunction of the harness wire
OK
Check trouble symptom.NG
Check the harness wire between thepower supply and diagnostic connector(16-pin), and repair if necessary.
Measure at the diagnosis connector(16-pin) B-18.� Voltage between 16 and earth
OK: Battery voltage
NGCheck the following connectors.B-67, B-74
NGRepair
OK
Measure at the diagnosis connector(16-pin) B-18.� Continuity between 4 and earth� Continuity between 5 and earth
OK: Continuity
NGCheck the following connector.B-47
OKCheck trouble symptom.
NG
Repair
NG
Check the harness wire between thediagnostic connector (16-pin) and earth,and repair if necessary.OK
Replace the MUT-II.
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13A FUEL MPI 1999 – General/General Information
MULTIPOINT FUEL INJECTION (MPI) <4G9>GENERALOUTLINE OF CHANGE� 4G93 engines have been added in vehicles for New Zealand. Service procedures are basically the
same as the conventional 4G93 engines in vehicles for Australia.� The diagnosis connector power supply circuit has been changed in 4G93 engines for Australia and
New Zealand.� The following items have been changed to correspond to the addition of stronger exhaust gas purification
measures in vehicles with 4G93 engine for Australia.(1) The shape of the air flow sensor connector has been changed.(2) The fixed SAS has been abolished to correspond to changes in the throttle body. In addition,
the shape of the stepper motor connector has been changed.(3) The idle position switch has been abolished.(4) An evaporative emission control system utilizing a purge control solenoid has been adopted.
� The following items have been changed to correspond to specification changes to the 4G92 enginein vehicles for GCC.(1) The fixed SAS has been abolished to correspond to changes in the throttle body. In addition,
the shape of the stepper motor connector has been changed.(2) The idle position switch has been abolished.
GENERAL INFORMATIONGENERAL SPECIFICATIONS
Itemes Specifications
Engine-ECU Identification No. E2T73175 <Vehicles for GCC>E2T73772 <Vehicles for Australia with strength-ened exhaust gas purification measures>
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13A FUEL MPI 1999 – General Information
MULTI-POINT FUEL INJECTION SYSTEM DIAGRAM
*1 Oxygen sensor*2 Air flow sensor*3 Intake air temperature sensor*4 Throttle position sensor*5 Camshaft position sensor*6 Crank angle sensor*7 Barometric pressure sensor*8 Engine coolant temperature sensor
� Power supply voltage� Vehicle speed sensor� A/C switch� Inhibitor switch� Power steering fluid pressure switch� Ignition switch – ST� Ignition switch – IG� Alternator FR terminal
�1 Injector�2 Idle speed control servo�3 Purge control solenoid valve
� Fuel pump relay� Control relay� A/C power relay� Engine warning lamp� Diagnosis signal� Ignition coil, power transistor� Fan motor relay� Alternator G terminal
Engine-ECU
�2 Idle speed control servo
*3 Intake air temperature sensor
Air flow sensor(with barometricpressure sensor)
Throttle position sensor
Canister
*6 Crank angle sensor
Catalytic converter
*1Oxygen sensor
*8 Engine coolant temperature sensor
�1 Injector
From fuelpump
*5 Camshaft position sensor
Fuel pressure regulator
Purge controlsolenoidvalve
Air cleanerAir
*2*7
P
*4
To fueltank
PCV valve
�3
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13A FUEL MPI 1999 – Service Specifications/Special Tools/Troubleshooting
SERVICE SPECIFICATIONS
Items Specifications
Throttle position sensor adjusting voltage mV 535 – 735
SPECIAL TOOLS
Tool Number Name Use
MB991709 Test harness � Measurement of voltage during troubleshooting
� Inspection using an analyzer� Inspection of idle speed control servo
MB991536 Check harness forPS adjustment
� Adjusting the throttle position sensor
TROUBLESHOOTINGINSPECTION CHART FOR DIAGNOSIS CODES
Code No. Diagnosis item
12 Air flow sensor system
13 Intake air temperature sensor system
14 Throttle position sensor system
21 Engine coolant temperature sensor system
22 Crank angle sensor system
23 Camshaft position sensor
24 Vehicle speed sensor system
25 Barometric pressure sensor system
31 Detonation sensor system
41 Injector system
44 Ignition coil and power transistor unit system
54 Immobilizer system
61 Communication wire with A/T-ECU system <A/T>
64 Alternator FR terminal system
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE FOR DIAGNOSIS CODES
Code No. 12 Air flow sensor system <Vehicles forAustralia with strengthened exhaust gas purificationmeasures>
Probable cause
Range of Check� Engine speed is 500 r/min. or more.Set conditions� Sensor output frequency is 3 Hz or less for 4 seconds.
� Malfunction of the air flow sensor� Improper connector contact, open circuit or
short-circuited harness wire of the air flow sensor� Malfunction of the engine-ECU
NG
OKOK
2. NGMeasure at the engine-ECU connectorB-37.� Connect the connector.� Voltage between 19 and earth (Igni-
tion switch: ON)OK: 6 – 9 V
NGCheck the following connector.A-101
Measure at the air flow sensor connectorA-101.� Connect the connector. (Use the test
harness: MB991709)1. Voltage between 3 and earth
(Engine: Idling)OK: 2.2 – 3.2 V
2. Voltage between 7 and earthOK: 0 – 1 V (Engine: idling)
6 – 9 V (2,000 r/min.)
1. NGCheck the air flow sensor circuit. (ReferINSPECTION PROCEDURE 45.)
Replace the engine-ECU. NGCheck the following connector.B-37
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
OK
Check trouble symptom.
NG
Replace the air flow sensor.
Repair
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13A FUEL MPI 1999 – Troubleshooting13A FUEL MPI 1999 – Troubleshooting
Code No. 13 Intake air temperature sensor system<Vehicles for Australia with strengthened exhaust gaspurification measures>
Probable cause
Range of Check� Ignition switch: ON� Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.Set conditions� Sensor output voltage is 4.6 V or more (corresponding to an intake air temperature
of –45°C or less) for 4 seconds.or� Sensor output voltage is 0.2 V or less (corresponding to an intake air temperature
of 125°C or more) for 4 seconds.
� Malfunction of the intake air temperature sensor� Improper connector contact, open circuit or
short-circuited harness wire of the intake airtemperature sensor circuit
� Malfunction of the engine-ECU
OKNG
Check the intake air temperature sensorNG
Replace
Measure at the air flow sensor connectorA-101.� Disconnect the connector, and mea-
sure at the harness side.� Voltage between 6 and earth (Igni-
tion switch: ON)OK: 4.5 – 4.9 V
� Continuity between 5 and earthOK: Continuity
Check the following connector.B-34
OK
Check the following connector.A-101
NGRepair
OK
Check trouble symptom.NG
Replace the engine-ECU.
OK
Check trouble symptom.
NG
Check the harness wire between theengine-ECU and the intake air tempera-ture sensor connector.
OK
Replace the engine-ECU.
NG
Repair
NG
Repair
Code No. 14 Throttle position sensor system Probable causeRange of Check� Ignition switch: ON� Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.Set conditions� Engine speed is 3,000 r/min or less, and volumetric efficiency is 30% or less,
TPS output voltage is 4.6 V or more for 4 seconds.or� Engine speed is 2,000 r/min or more, and volumetric efficiency is 60% or more,
TPS output voltage is 0.8 V or less for 4 seconds.
� Malfunction of the throttle position sensor ormaladjustment
� Improper connector contact, open circuit orshort-circuited harness wire of the throttle positionsensor circuit
� Malfunction of the engine-ECU
OK
OK
Replace the engine-ECU.
NGNG
Check the harness wire between theengine-ECU and the throttle positionsensor connector.
Repair
Check the throttle position sensor. NG
Replace
Measure at the throttle position sensorconnector A-05.� Disconnect the connector, and mea-
sure at the harness side.� Voltage between 1 and earth
(Ignition switch: ON)OK: 4.8 – 5.2 V
� Continuity between 4 and earthOK: Continuity
NGCheck the following connector.B-34
NGRepair
OK
Check the throttle position sensor outputcircuit. (Refer INSPECTION PROCED-URE 46 <Vehicles for Australia>
OK
Check trouble symptom.
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13A FUEL MPI 1999 – Troubleshooting
Code No. 25 Barometric pressure sensor system<Vehicles for Australia with strengthened exhaust gaspurification measures>
Probable cause
Range of Check� Ignition switch: ON� Excluding 60 seconds after the ignition switch is turned to ON or immediately
after the engine starts.� Battery voltage is 8 V or more.Set conditions� Sensor output voltage is 4.5 V or more (corresponding to a barometric pressure
of 114 kPa or more) for 4 seconds.or� Sensor output voltage is 0.2 V or less (corresponding to a barometric pressure
of 5.33 kPa or less) for 4 seconds.
� Malfunction of the barometric pressure sensor� Improper connector contact, open circuit or
short-circuited harness wire of the barometric pressuresensor circuit
� Malfunction of the engine-ECU
Measure at the air flow sensor connectorA-101.� Connect the connector. (Use the test
harness: MB991709)� Voltage between 2 and earth (Igni-
tion switch: ON)OK: 3.7 – 4.3 V (Altitude: 0 m)
3.2 – 3.8 V (Altitude: 1,200m)
NGMeasure at the air flow sensor connectorA-101.� Disconnect the connector, and mea-
sure at the harness side.� Voltage between 1 and earth (Igni-
tion switch: ON)OK: 4.8 – 5.2 V
� Continuity between 5 and earthOK: Continuity
NGCheck the following connector.B-34
OK
Measure at the engine-ECU connectorB-34.� Connect the connector.� Voltage between 85 and earth (Igni-
tion switch: ON)OK: 3.7 – 4.3 V (Altitude: 0 m)
3.2 – 3.8 V (Altitude: 1,200m)
NGCheck the harness wire between theengine-ECU and the barometric pres-sure sensor connector, and repair if nec-essary.
OK
Check the following connector. B-34NG
Repair
OK
Check trouble symptom.
NG
Replace the engine-ECU.
NG
OK
Check the following connector.A-101
Repair
OK
Check trouble symptom.
NGNG
Check the harness wire between theengine-ECU and the barometric pres-sure sensor connector.
Repair
OK
Check trouble symptom.
NG
Check the harness wire between theengine-ECU and the barometric pres-sure sensor connector.
Replace the engine-ECU.
NG
Repair
NG
Repair
OK
Replace the air flow sensor.OK
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION CHART FOR TROUBLE SYMPTOMS
Trouble symptom InspectionprocedureNo.
Communication with Communication with all systems is not possible. 1MUT-II is impossible.
Communication with engine-ECU only is not possible. 2
Engine warning lampand related parts
The engine warning lamp does not illuminate right after the ignition switch isturned to the ON position.
3
The engine warning lamp remains illuminating and never goes out. 4
Starting No initial combustion (starting impossible) 5
Initial combustion but no complete combustion(starting impossible)
6
Long time to start (improper starting) 7
Idling stability Unstable idling (Rough idling, hunting) 8(Improper idling)
Idling speed is high. (Improper idling speed) 9
Idling speed is low. (Improper idling speed) 10
Idling stability When the engine is cold, it stalls at idling. (Die out) 11(Engine stalls)
When the engine becomes hot, it stalls at idling. (Die out) 12
The engine stalls when starting the car. (Pass out) 13
The engine stalls when decelerating. 14
Driving Hesitation, sag or stumble 15
The feeling of impact or vibration when accelerating 16
The feeling of impact or vibration when decelerating 17
Poor acceleration 18
Surge 19
Knocking 20
Dieseling 21
Too high CO and HC concentration when idling 22
Low alternator output voltage (approx. 12.3 V) 23
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE FOR TROUBLE SYMPTOMSINSPECTION PROCEDURE 1 <Vehicles for Australia and New Zealand>
Communication with MUT-II is not possible.(Communication with all systems is not possible.)
Probable cause
The cause is probably a defect in the power supply system (including earth) for thediagnosis line.
� Malfunction of the connector� Malfunction of the harness wire
Measure at the diagnostic connector(16-pin) B-18.� Voltage between 16 and earth
OK: Battery voltage
NGCheck the following connectors.B-67, B-74
NGRepair
OK
Check trouble symptom.NG
Check the harness wire between thepower supply and diagnostic connector(16-pin), and repair if necessary.
OK
Measure at the diagnostic connector(16-pin) B-18.� Continuity between 4 and earth� Continuity between 5 and earth
OK: Continuity
NGCheck the following connector.B-47
OKCheck trouble symptom.
OK
Replace the MUT-II.
NG
Check the harness wire between thediagnostic connector (16-pin) and earth,and repair if necessary.
NG
Repair
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 6
Initial combustion but no complete combustion (starting impossible)
Probable cause
In such cases as the above, the cause is probably that the spark plugs are generatingsparks but the sparks are weak, or the initial mixture for starting is not appropriate.
� Malfunction of the ignition system� Malfunction of the injector system� Foreign materials in fuel� Poor compression� Malfunction of the engine-ECU
OK
OK
Check battery voltage when cranking.OK: 8 V or higher
NGCheck the battery
MUT-II: Check if uncompleted combustion occurs.(Refer INSPECTION PROCEDURE 36.)
OK
Can any sound be heard from the injectors when cranking?NG
Check the injector system, (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
Is starting good if the engine is cranked with the accelerator pedalslightly depressed?
YesCheck ISC servo for operation sound.
NGCheck the ISC servo sys-tem. (Refer INSPECTIONPROCEDURE 33)
OK
� Clean the throttle body.
Check the following items.� Check the ignition coil, spark plugs, spark plug cables� Check if the injectors are clogged.� Check the compression pressure.� Check fuel lines for clogging.� Check if foreign materials (water, alcohol, etc.) got into fuel.
No
Check the ignition timing when cranking.OK: Approx. 5°BTDC
NGCheck that the crank angle sensor is installed properly.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 8
Unstable idling (Rough idling, hunting) Probable causeIn cases as the above, the cause is probably that the ignition system, air/fuel mixture,idle speed control (ISC) or compression pressure is defective.Because the range of possible causes is broad, inspection is narrowed down to simpleitems.
� Malfunction of the ignition system� Malfunction of air-fuel ratio control system� Malfunction of the ISC system� Malfunction of the purge control solenoid valve system
<Vehicles for Australia>� Malfunction of the EGR solenoid valve system
<Vehicles for GCC>� Poor compression� Drawing air into exhaust system
OK
Were the battery terminals disconnected?Yes
After warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Does idling speed fluctuate excessively?Yes
Check if hunting occurs.(Refer INSPECTION PROCEDURE 37.)
No
Check the ISC servo for operation sound.NG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)
OK
Check the injector for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
MUT-II: Check if idling speed is unstable.(Refer INSPECTION PROCEDURE 38.)
OK
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
Check the following items.� Check the ignition coil, spark plugs, spark plug cables.� Check the purge control system.� Check the EGR control system.� Check the compression pressure.� Check if foreign materials (water, alcohol, etc.) got into fuel.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 9
Idling speed is high. (Improper idling speed) Probable causeIn such cases as the above, the cause is probably that the intake air volume duringidling is too great.
� Malfunction of the ISC servo system� Malfunction of the throttle body
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation sound.NG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system.(Refer INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
MUT-II Data list28 A/C switch
NGCheck the A/C switch and A/C relay system.(Refer INSPECTION PROCEDURE 30.)
Basic idle adjustment
Check trouble symptom.NG
Clean the throttle valve area.
INSPECTION PROCEDURE 10
Idling speed is low. (Improper idling speed) Probable causeIn cases such as the above, the cause is probably that the intake air volume duringidling is too small.
� Malfunction of the ISC servo system� Malfunction of the throttle body
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation soundNG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system.(Refer INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
MUT-II Data list29 Inhibitor switch
NGCheck the ignition switch ST and inhibitor switch system <A/T>.(Refer INSPECTION PROCEDURE 28.)
Basic idle adjustment
Check trouble symptom.NG
Clean the throttle body.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 11
When the engine is cold, it stalls at idling. (Die out) Probable causeIn such cases as the above, the cause is probably that the air/fuel mixture is inappropriatewhen the engine is cold, or that the intake air volume is insufficient.
� Malfunction of the ISC servo system� Malfunction of the throttle body� Malfunction of the injector system� Malfunction of the ignition system
OK
OK
Were the battery terminals disconnected?Yes
After warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Does the engine stall right after the accelerator pedal is released?Yes
Clean the throttle body.
No
Is engine-idling stable after the warming-up?No
Check if the unstable idling (Rough idling, hunting).(Refer INSPECTION PROCEDURE 8.)
Check the fuel pressure.
OK
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
Yes
Check the ISC servo for operation sound.NG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)
OK
Check the injector for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
Check the following items.� Check the ignition coil, spark plugs, spark plug cables� Check the compression pressure.� Check the engine oil viscosity.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 12
When the engine is hot, it stalls at idling. (Die out) Probable causeIn such cases as the above, the cause is probably that ignition system, air/fuel mixture,idle speed control (ISC) or compression pressure is defective.In addition, if the engine suddenly stalls, the cause may also be a defective connectorcontact.
� Malfunction of the ignition system� Malfunction of air-fuel ratio control system� Malfunction of the ISC system� Drawing air into intake system� Improper connector contact
No
OK
Were the battery terminals disconnected?Yes
After warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation sound.NG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)
OK
Check the injector for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
Yes
MUT-II: Engine stalling inspection when the engine is warm andidling. (Refer INSPECTION PROCEDURE 39.)
OK
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
OK
Does the engine stall right after the accelerator pedal is released?Yes
Clean the throttle valve area.
Does the engine stall easily again?No
While carrying out an intermittent malfunction simulation test (Refer – Points Note for Intermittent Malfunctions.), check for sud-den changes in the signals shown below.� Crank angle sensor signal� Air flow sensor signal� Injector drive signal� Primary and secondary ignition signal� Fuel pump drive signal� Engine-ECU power supply voltage
Check the following items.� Check the ignition coil, spark plugs, plug cables� Check if the injectors are clogged.� Check the compression pressure.� Check if foreign materials (water, alcohol, etc.) got into fuel.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 14
The engine stalls when decelerating. Probable causeIn cases such as the above, the cause is probably that the intake air volume is insufficientdue to a defective idle speed control (ISC) servo system.
� Malfunction of the ISC system
Were the battery terminals disconnected?Yes
After warming-up, let the engine run at idling for 10 minutes.
No
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
MUT-II Data list14 Throttle position sensor
NGCheck the throttle position sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list45 ISC servo position� Is the idle speed control (ISC) servo position drops to 0 – 2
steps when decelerating (engine r/min less than 1,000)?
YesCheck the vehicle speed sensor system. (Refer INSPECTION PROCEDURE FOR DIAGNOSIS CODE 24.)
No
Check the following items.� Check the ignition coil, spark plugs, spark plug cables.� Clean the throttle body.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 15
Hesitation, sag or stumble Probable causeIn cases such as the above, the cause is probably that ignition system, air/fuel mixtureor compression pressure is defective.
� Malfunction of the ignition system� Malfunction of air-fuel ratio control system� Malfunction of the fuel supply system� Malfunction of the EGR control solenoid valve system
<Vehicles for GCC>� Poor compression
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.(Refer INSPECTION PROCEDURE 40.)
OK
Check the fuel pressure.
Check the following items.� Check the ignition coil, spark plugs, spark plug cables.� Check the compression pressure.� Check the fuel filter or fuel for clogging.
OK
Check the ignition timingNG
Check that the crank angle sensor is installed properly.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 17
The feeling of impact or vibration when decelerating Probable causeMalfunction of the ISC system is suspected. � Malfunction of the ISC system
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ISC servo for operation sound.NG
Check the ISC servo system.(Refer INSPECTION PROCEDURE 33.)
OK
MUT-II Data list14 Throttle position sensor
NGCheck the throttle position sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
Clean the throttle body.
INSPECTION PROCEDURE 18
Poor acceleration Probable causeDefective ignition system, abnormal air-fuel ratio, poor compression pressure, etc.are suspected.
� Malfunction of the ignition system� Malfunction of air-fuel ratio control system� Malfunction of the fuel supply system� Poor compression pressure� Clogged exhaust system
OK
OK
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
MUT-II: Check if hesitation, sag, stumble or poor acceleration occur.(Refer INSPECTION PROCEDURE 40.)
Check the fuel pressure.
Check the following items.� Check the ignition coil, spark plugs, spark plug cables.� Check the compression pressure.� Check the fuel filter or fuel line for clogging.� Broken air intake hose� Clogged air cleaner
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 19
Surge Probable causeDefective ignition system, abnormal air-fuel ratio, etc. are suspected. � Malfunction of the ignition system
� Malfunction of air-fuel ratio control system� Malfunction of the EGR control solenoid valve system
<Vehicles for GCC>
OK
OK
OK
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the injectors for operation sound.NG
Check the injector system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 41.)
OK
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
MUT-II: Check if surge occurs. (ReferINSPECTION PROCEDURE 41.)
Check the fuel pressure.
Check the following items.� Check the ignition coil, spark plugs, spark plug cables.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 22
Too high CO and HC concentration when idling Probable causeAbnormal air-fuel ratio is suspected. � Malfunction of the air-fuel ratio control system
� Deteriorated catalyst
OK
NG
MUT-II Self-Diag codeAre diagnosis codes displayed?
YesRefer INSPECTION CHART FOR DIAGNOSIS CODES.
No
Check the ignition timing.NG
Check that the crank angle sensor is installed properly.
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system.(Refer INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
Check the following items.� Check the injectors for operation sound.� Check the injectors for fuel leakage.� Check the ignition coil, spark plugs, spark plug cables� Check the compression pressure.� Check the positive crankcase ventilation system.� Check the purge control system.
Check the trouble symptom.
Replace the catalytic converter.
Check the fuel pressure.
OK
MUT-II Data list13 Intake air temperature sensor
NGCheck the intake air temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list25 Barometric pressure sensor
NGCheck the barometric pressure sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list11 Oxygen sensor
OK: Repeat 0 – 400 mV and 600 – 1,000 mV alternately whenidling.
OKReplace the oxygen sensor.
OK
MUT-II Data list11 Oxygen sensor
OK: 600 – 1,000 mV when racing suddenly
NGCheck the oxygen sensor system. (Refer INSPECTION PROCEDURE 49.)
Check trouble symptom.NG NG
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 33 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Idle speed control (ISC) servo (Stepper motor) system Probable causeThe engine-ECU controls the intake air volume during idling by opening and closingthe servo valve located in the bypass air passage.
� Malfunction of ISC servo� Improper connector contact, open circuit or
short-circuited harness wire� Malfunction of the engine-ECU
OK
OK
OK
Measure at the ISC servo connector A-56.� Disconnect the connector and measure at the harness side.� Voltage between 2 and earth, and 5 and earth (Ignition switch:
ON)OK: System voltage
NGCheck the harness wire between control relay and ISC servo con-nector, and repair if necessary.
Check the ISC servoNG
Replace
Measure at the engine-ECU connector B-37.� Disconnect the connector, measure at the harness side.� Voltage between each of 4, 5, 17, 18 and earth (Ignition switch:
ON)OK: System voltage
NGCheck the followingconnector. A-56
NGRepair
Check trouble symptom.
NG
Check harness wire between engine-ECU and ISC servo connector,and repair if necessary.
OK
Check the followingconnector. B-37
NGRepair
Check trouble symptom.NG
Replace the engine-ECU.
OK
INSPECTION PROCEDURE 37 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Check if hunting occurs.
Clean the throttle body.
Check trouble symptom.
NG
Inspect the intake of air into the air intake system� Broken intake manifold gasket� Broken air intake hose� Broken vacuum hose� Positive crankcase ventilation valve does not operate.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 38 <Vehicles for Australia>
MUT-II: Check if idling speed is unstable.
<Vehicles for Australia with strengthened exhaust gas purification measures>
OK
OK
MUT-II Data list28 A/C switch
NGCheck the A/C switch and A/C relay system. (ReferINSPECTION PROCEDURE 30.)
OK
MUT-II Data list27 Power steering fluid pressure switch
NGCheck the power steeringfluid pressure switch sys-tem. (Refer INSPECTIONPROCEDURE 29.)
MUT-II Data list13 Intake air temperature sensor
NGCheck the intake air temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list25 Barometric pressure sensor
NGCheck the barometric pressure sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system.(Refer INSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
MUT-II Actuator test08 Purge control solenoid valve
NGCheck the purge control solenoid valve system.(Refer INSPECTION PROCEDURE 48.)
OK
MUT-II Data list11 Oxygen sensor
OK: 600 – 1,000 mV during sudden racing
NGCheck the oxygen sensor system. (ReferINSPECTION PROCEDURE 49.)
MUT-II Data list11 Oxygen sensor
OK: Changes between 0 – 400 mV and 600 – 1,000 mV duringidling
NGCheck the fuel pressure.
OK1. Inspect the intake of
air into the air intakesystem.� Broken intake
manifold gasket� Broken vacuum
hose� PCV valve does
not operate.� Broken air intake
hose2. Check the injector for
clog.
OK
MUT-II Data list29 Inhibitor switch
NGCheck the ignition switch-ST and inhibitor switch system. <A/T>(Refer INSPECTION PROCEDURE 28.)
OK
MUT-II Data list45 ISC Servo position
NGAdjust the basic idle speed
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 39 <Vehicles for Australia>
MUT-II: Engine stalling inspection when the engine is warmed up and idling.
<Vehicles for Australia with strengthened exhaust gas purification measures>
OK
MUT-II Data list13 Intake air temperature sensor
NGCheck the intake air sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list25 Barometric pressure sensor
NGCheck the barometric pressure sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
MUT-II Actuator test08 Purge control solenoid valve
NGCheck the purge control solenoid valve system.(Refer INSPECTION PROCEDURE 48.)
OK
MUT-II Data list11 Oxygen sensor
OK: Changes between 600 – 1,000 mV during sudden racing
NGCheck the oxygen sensor system. (ReferINSPECTION PROCEDURE 49.)
MUT-II Data list11 Oxygen sensor
OK: Changes between 0 – 400 mV and 600 – 1,000 mV duringidling
NGCheck the fuel pressure.
OK1. Inspect the intake of
air into the air intakesystem� Broken intake
manifold gasket� Broken vacuum
hose� PCV valve does
not operate.� Broken air intake
hose2. Check the injector for
clog.
OK
MUT-II Data list27 Power steering fluid pressure switch
NGCheck the power steeringfluid pressure switch sys-tem. (Refer INSPECTIONPROCEDURE 29.)OK
MUT-II Data list28 A/C switch
NGCheck the A/C switch and A/C relay system.(Refer INSPECTION PROCEDURE 30.)
OK
MUT-II Data list29 Inhibitor switch
NGCheck the ignition switch-ST and inhibitor switch system. <A/T>(Refer INSPECTION PROCEDURE 28.)
OK
MUT-II Data list45 ISC servo position
NGAdjust the basic idle speed.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 40 <Vehicles for Australia>
MUT-II: Check if hesitation, sug, stumble or poor acceleration occurs.
<Vehicles for Australia with strengthened exhaust gas purification measures>
OK
OK
MUT-II Data list25 Barometric pressure sensor
NGCheck the barometric pressure sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
MUT-II Data list13 Intake air temperature sensor
NGCheck the intake air temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSTIC CODE 21.)
OK
MUT-II Data list14 Throttle position sensor
NGCheck the throttle position sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list11 Oxygen sensor
OK: Changes between 600 – 1,000 mV during sudden racing
NGCheck the oxygen sensor system. (Refer INSPECTION PROCEDURE 49.)
MUT-II Data list11 Oxygen sensor
OK: Changes between 0 – 400 mV and 600 – 1,000 mV duringidling
NGCheck the fuel pressure.
OK1. Inspect the intake of
air into the air intakesystem� Broken intake
manifold gasket� Broken vacuum
hose� PCV valve does
not operate.� Broken air intake
hose2. Check the injector for
clog.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 41 <Vehicles for Australia>
MUT-II: Check if surge occurs.
<Vehicles for Australia with strengthened exhaust gas purification measures>
OK
OK
MUT-II Data list13 Intake air temperature sensor
NGCheck the intake air temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 13.)
OK
MUT-II Data list25 Barometric pressure sensor
NGCheck the barometric pressure sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 25.)
MUT-II Data list21 Engine coolant temperature sensor
NGCheck the engine coolant temperature sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 21.)
OK
MUT-II Data list14 Throttle position sensor
NGCheck the throttle position sensor system. (ReferINSPECTION PROCEDURE FOR DIAGNOSIS CODE 14.)
OK
MUT-II Data list11 Oxygen sensor
OK: Changes between 600 – 1,000 mV during sudden racing
NGCheck the oxygen sensor system. (ReferINSPECTION PROCEDURE 49.)
MUT-II Data list11 Oxygen sensor
OK: Changes between 0 – 400 mV and 600 – 1,000 mV duringidling
NGCheck the fuel pressure.
OK1. Inspect the intake of
air into the air intakesystem� Broken intake
manifold gasket� Broken vacuum
hose� PCV valve does
not operate.� Broken air intake
hose2. Check the injector for
clog.
INSPECTION PROCEDURE 45 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Check air flow sensor (AFS) control circuit.
OK
2, 3. NGCheck the followingconnector. B-34
NGRepair
Measure at the air flow sensor connector A-101.� Disconnect the connector and measure at the harness side.1. Voltage between 4 and earth (Ignition switch: ON)
OK: System voltage2. Voltage between 3 and earth (Ignition switch: ON)
OK: 4.8 – 5.2 V3. Continuity between 5 and earth
OK: Continuity
1. NGCheck the harness wire between the air flow sensor and controlrelay connector, and repair if necessary.
Check trouble symptom.
NG
Check the harness wirebetween the engine-ECUand air flow sensor con-nector.
NGRepair
OK
Replace the engine-ECU.
OK
Check the following connector. A-101
OK
Check trouble symptom.
NG
Replace the air flow sensor.
NG
Repair
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 46 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Check throttle position sensor (TPS) output circuit.
OK
NG
OKCheck the followingconnector. B-34
NGRepairMeasure at the engine-ECU connector B-34.
� Connect the connector.� Voltage between 84 and earth (Ignition switch: ON)
OK: 0.535 – 0.735 V (Throttle valve at idle position)4.5 – 5.5 V (Throttle valve fully open) Check trouble symptom.
OK
Check trouble symptom.
Check the harness wire between engine-ECU and throttle positionsensor connector, and repair if necessary.
NG
Replace the engine-ECU.
NG
Check the following connector. A-05NG
Repair
INSPECTION PROCEDURE 48 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Purge control solenoid valve system Probable causeThe purge control solenoid valve controls the purging of air from the canister locatedinside the intake manifold.
� Malfunction of solenoid valve� Improper connector contact, open circuit or
short-circuited harness wire.� Malfunction of the engine-ECU
NG
OK
OK
OK
Measure at the purge control solenoid valve connector A-81.� Disconnect the connector and measure at the harness side.� Voltage between 2 and earth (Ignition switch: ON)
OK: system voltage
NGCheck the harness wire between control relay and solenoid valveconnector, and repair if necessary.
Check the purge control solenoid valve.NG
Replace
Measure at the engine-ECU connector B-37.� Disconnect the connector and measure at the harness side.� Voltage between 9 and earth (Ignition switch: ON)
OK: system voltage
NGCheck the followingconnector. A-81
NGRepair
OK
Check the followingconnector. B-37
NGRepair
Check trouble symptom.
NG
Check the harness wire between engine-ECU and solenoid valveconnector, and repair if necessary.OK
Check trouble symptom.
Replace the engine-ECU.
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE 49 <Vehicles for Australia with strengthened exhaust gaspurification measures>
Oxygen sensor system Probable causeIf the CO and HC contents are high, the probable causes mentioned to the rightcolumn are suspected.� The oxygen sensor detects the oxygen content in exhaust gas, converts it to
voltage, and sends the voltage to the engine-ECU.� The engine-ECU controls the fuel injection amount to adjust the air/fuel ratio to
theoretical one.
� Malfunction of the oxygen sensor� Improper connector contact, open circuit or
short-circuited harness wire� Malfunction of the engine-ECU
OK
NG
OK
OK
OK
NG
OK
Check the oxygen sensorNG
Replace
Measure at the oxygen sensor connector A-87.� Disconnect the connector, and measure at the harness side.� Continuity between 2 and earth
OK: Continuity
NGCheck the following connector.B-34
NGRepair
Check the harness wire between theengine-ECU and the oxygen sensorconnector.
NGRepair
Replace the engine-ECU.
Check trouble symptom.OK
Check the following connector.A-87
NGRepair
Check trouble symptom.
Check the harness wire between the engine-ECU and the oxygensensor connector.
NGRepair
Replace the engine-ECU.
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13A FUEL MPI 1999 – Troubleshooting
DATA LIST REFERENCE TABLE
CautionWhen shifting the select lever to D range, the brakes should be applied so that the vehicle doesnot move forward.
NOTE*1. In a new vehicle [driven approximately 500 km or less], the air flow sensor output frequency is sometimes
10% higher than the standard frequency.*2. When idling to warm up from an engine coolant temperature of approx. –20�C, if the idling speed
is lower than the standard value even when the ISC motor is fully opened, the air volume limiterbuilt in the throttle body could be defective.
*3. The injector drive time represents the time when the cranking speed is at 250 r/min. or below whenthe power supply voltage is 11 V.
*4. In a new vehicle [driven approximately 500 km or less], the injector drive time is sometimes 10%longer than the standard time.
*5. In a new vehicle [driven approximately 500 km or less], the step of the stepper motor is sometimes30 steps greater than the standard value.
ItemNo.
Inspectionitem
Inspection contents Normal condition Inspection procedure No.
11 Oxygensensor
Engine: After havingwarmed upAir/fuel mixture ismade leaner when
When at 4,000 r/min,engine is suddenlydecelerated
200 mV or less Procedure No. 49
made leaner whendecelerating, and ismade richer whenracing.
When engine is sud-denly raced
600 – 1,000 mV
Engine: After havingwarmed upThe oxygen sensorsignal is used to
Engine is idling 400 mV or less(Changes)600 – 1,000 mV
check the air/fuelmixture ratio, andcontrol condition isalso checked by theECU.
2,500 r/min 400 mV or less(Changes)600 – 1,000 mV
12 Air flowsensor*1
� Engine coolanttemperature:
�
Engine is idling 25 – 51 Hz –
80 – 95�C� Lamps, electric
cooling fan and all
2,500 r/min 80 – 120 Hz
cooling fan and allaccessories:OFF
� Transmission:Neutral (A/T:P range)
Engine is raced Frequencyincreases inresponse toracing
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13A FUEL MPI 1999 – Troubleshooting
ItemNo.
Inspection procedure No.Normal conditionInspection contentsInspectionitem
13 Intake airtempera-
Ignition switch: ONor with engine
When intake airtemperature is –20�C
–20�C Code No.13
turesensor
runningWhen intake airtemperature is 0�C
0�C
When intake airtemperature is 20�C
20�C
When intake airtemperature is 40�C
40�C
When intake airtemperature is 80�C
80�C
14 Throttle Ignition switch: ON Set to idle position 535 – 735 mV Code No.14positionsensor Gradually open Increases in
proportion tothrottle openingangle
Open fully 4,500 – 5,500 mV
16 Powersupplyvoltage
Ignition switch: ON System voltage ProcedureNo. 24
17 Mixtureadjustingscrew(variableresistor)
Ignition switch: ON 1,000 – 4,000 mV Procedure No. 32
18 Crankingsignal
Ignition switch: ON Engine: Stopped OFF Procedure No. 27 <M/T>Procedure No. 28 <A/T>signal
(ignitionswitch-ST) Engine: Cranking ON
Procedure No. 28 <A/T>
21 Enginecoolant
Ignition switch: ONor with engine
When engine coolanttemperature is –20�C
–20�C Code No.21
tempera-turesensor
runningWhen engine coolanttemperature is 0�C
0�C
When engine coolanttemperature is 20�C
20�C
When engine coolanttemperature is 40�C
40�C
When engine coolanttemperature is 80�C
80�C
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13A FUEL MPI 1999 – Troubleshooting
ItemNo.
Inspectionitem
Inspection contents Normal condition Inspection procedure No.
22 Crankanglesensor*2
� Engine: Cranking� Tachometer:
Connected
Compare the enginespeed readings onthe tachometer andthe MUT-II.
Accord Code No.22
� Engine: Idling When engine coolanttemperature is –20�C
1,400 – 1,600r/min
When engine coolanttemperature is 0�C
1,350 – 1,550r/min
When engine coolanttemperature is 20�C
1,300 – 1,500r/min
When engine coolanttemperature is 40�C
1,100 – 1,300r/min
When engine coolanttemperature is 80�C
650 – 850 r/min
25 Baromet- Ignition switch: ON At altitude of 0 m 101 kPa Code No.25ricpressure At altitude of 600 m 95 kPasensor
At altitude of 1,200 m 88 kPa
At altitude of 1,800 m 81 kPa
27 Powersteering
Engine: Idling Steering wheelstationary
OFF Procedure No. 29
fluid pres-sureswitch
Steering wheelturning
ON
28 A/C switch Engine: Idling(when A/C switch is
A/C switch: OFF OFF Procedure No. 30
ON, A/C compres-sor should be oper-ating.)
A/C switch: ON ON
29 Inhibitor Ignition switch: ON P or N P or N ProcedureNo. 28switch<A/T> D, 2, L or R D, 2, L or R
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13A FUEL MPI 1999 – Troubleshooting
ItemNo.
Inspectionitem
Inspection contents Normal condition Inspection procedure No.
41 Injector*3 Engine: Cranking When engine coolanttemperature is 0�C(injection is carriedout for all cylinderssimultaneously)
13 – 19 ms –
When engine coolanttemperature is 20�C
27 – 40 ms
When engine coolanttemperature is 80�C
5.9 – 8.9 ms
Injector*4 � Engine coolanttemperature:80 – 95�C
Engine is idling 1.7 – 2.9 ms
80 – 95 C� Lamps, electric
cooling fan and allaccessories:
2,500 r/min 1.4 – 2.6 ms
OFF� Transmission:
Neutral (A/T:P range)
When engine issuddenly raced
Increases
44 Ignitioncoils andpowertransistors
� Engine: Afterhaving warmedup
� Timing lamp is
Engine is idling 2 – 18�BTDC –
set. (The timinglamp is set inorder to checkactual ignitiontiming.)
2,500 r/min 30 – 50�BTDC
45 ISC(stepper)motor
5
� Engine: coolanttemperature: 80– 95�C
�
A/C switch: OFF 2 – 25 STEP –
position*5 � Lamps, electriccooling fan and allaccessories:OFF
� Transmission:
A/C switch:OFF → ON
Increases by10 – 70 steps
Neutral (A/T:P range)
� Engine: Idling� When A/C switch
is ON, A/C com-pressor should beoperating
� A/C switch: OFF� Select lever:
N range → Drange
Increases by5 – 50 steps
49 A/C relay Engine: After havingwarmed up/Engineis idling
A/C switch: OFF OFF (Compres-sor clutch is notoperating)
Procedure No. 30
A/C switch: ON ON (Compressorclutch is operat-ing)
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13A FUEL MPI 1999 – Troubleshooting
ACTUATOR TEST REFERENCE TABLE
ItemNo.
Inspectionitem
Drive contents Inspection contents Normal condition Inspection procedure No.
01 Injectors Cut fuel to No. 1injector
Engine:After having warmed up/
Idling conditionbecomes differ-
Code No. 41
02 Cut fuel to No. 2injector
Engine is idling(Cut the fuel supply to eachinjector in turn and check
ent (becomes un-stable).
03 Cut fuel to No. 3injector
cylinders which don’t affectidling.)
04 Cut fuel to No. 4injector
07 Fuel pump Fuel pump op-erates and fuelis recirculated.
� Engine:Cranking
� Fuelpump:ForceddrivingInspectaccord-
Pinch thereturn hosewith fingersto feel thepulse of thefuel beingrecircu-lated.
Pulse is felt. Procedure No. 25
ing toboth theabovecondi-tions.
Listen nearthe fueltank for thesound offuel pumpoperation.
Sound of opera-tion is heard.
08 Purgecontrolsolenoidvalve
Solenoid valveturns from OFFto ON.
Ignition switch: ON Sound of opera-tion can be heardwhen solenoidvalve is driven.
Procedure No. 48
17 Basic igni-tion timing
Set to ignitiontiming adjust-ment mode
Engine: IdlingTiming light is set
5� BTDC –
20 Condenserfan
Drive the fanmotors(condenser)
� Ignition switch: ON� A/C switch: ON
Fan motoroperates
Procedure No. 31
21 Radiatorfan
Drive the fanmotors(radiator)
� Ignition switch: ON Fan motoroperates
Procedure No. 31
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13A FUEL MPI 1999 – Troubleshooting
CHECK AT THE ENGINE-ECU TERMINALSTERMINAL VOLTAGE CHECK CHARTEngine-ECU Connector Terminal Arrangement� The engine-ECU specifications have been changed in vehicles for GCC and vehicles for Australia
with stronger exhaust gas purification measures. The following changes have been made to correspondto this. Other items are the same as before.(1) Terminal No. 87 of the engine-ECU has been changed to the idle position signal terminal for
A/T control to correspond to the abolition of idle switch input.(2) A purge control solenoid valve has been added to terminal No. 9 of the engine-ECU <Vehicles
for Australia with strengthened exhaust gas purification measures>
Terminal No. Check item Check condition (Engine condition) Normal condition
9 Purge control Ignition switch: ON System voltagesolenoid valve
Running at 3,000 r/min while engine iswarming up after having been started.
0 – 3 V
87 Idle position signal Ignition switch: ON Set throttle valve toidle position
0 – 1 V
Slightly open throttlevalve
4 V or more
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13A FUEL MPI 1999 – Troubleshooting
INSPECTION PROCEDURE USING ANANALYZERAIR FLOW SENSOR (AFS)� The shape of the air processor connector has been
changed in vehicles for Australia with 4G93 engine andstrengthened exhaust gas purification measures.Procedures other than the measurement method are thesame as before.
Measurement Method1. Disconnect the air flow sensor connector, and connect
the special tool (test harness: MB991709) in between.(All terminals should be connected.)
2. Connect the analyzer special patterns pickup to air flowsensor connector terminal 3.
Alternate Method(Test harness not available)1. Connect the analyzer special patterns pickup to
engine-ECU terminal 90.
STEPPER MOTOR� The shape of the stepper motor connector has been
changed to correspond to changes to the throttle body.Procedures other than the measurement method are thesame as before.
Measurement Method1. Disconnect the stepper motor connector, and connect
the special tool (test harness: MB991709) in between.(All terminals should be connected.)
2. Connect the analyzer special patterns pickup to thestepper motor-side connector terminal 1, terminal 3,terminal 4 and terminal 6 respectively.
Alternate Method(Test harness not available)1. Connect the analyzer special patterns pickup to
engine-ECU terminal 4, connection terminal 5, connectionterminal 17, and connection terminal 18 respectively.
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Specialpatternspickup
Analyzer
Special patterns pickup
Analyzer
13A FUEL MPI 1999 – On-vehicle Service
ON-VEHICLE SERVICE� The following service procedures have been established
to correspond to changes in the throttle body in vehicleswith 4G92 engine for GCC and vehicles for Australia4G93 engine and stronger exhaust gas purificationmeasures. Other procedures are the same as before.
THROTTLE POSITION SENSOR ADJUSTMENT1. Connect the MUT-II to the diagnosis connector. Carry
out the following procedure if not using the MUT-II.
(1) Disconnect the throttle position sensor connector andconnect the special tool (MB991536 test harness)between the disconnected connectors. (Be carefulnot to mistake the terminal numbers.)
(2) Connect a digital-type voltage meter between terminal(3) (sensor output: yellow clip of the special tool)and terminal (1) (sensor earth: red clip of specialtool) of the throttle position sensor connector.
2. Turn the ignition switch to ON. (Do not start the engine.)3. Check the throttle position sensor output voltage.
Standard value: 535 – 735 mV
4. If the voltage is outside the standard value range, loosenthe throttle position sensor mounting bolt and turn thethrottle position sensor body to adjust.
5. Turn the ignition switch to OFF.6. Disconnect the MUT-II. If not using the MUT-II, remove
the special tool and re-connect the throttle position sensorconnector.
7. If a diagnosis trouble code has been output, use theMUT-II to erase the diagnosis codes, or disconnect the(–) terminal of the battery for 10 seconds or more andthen reconnect it. Then run the engine at idle for about10 minutes.
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Throttle position sensor
MB991536 Throttle posi-tion sensor
13A FUEL MPI 1999 – On-vehicle Service
BASIC IDLE SPEED ADJUSTMENT
NOTE(1) The standard idling speed has been adjusted by the
speed adjusting screw (SAS) by the manufacturer,and there should usually be no need for readjustment.
(2) If the adjustment has been changed by mistake, theidle speed may become too high or the idle speedmay drop too low when loads from components suchas the A/C are placed on the engine. If this occurs,adjust by the following procedure.
(3) The adjustment, if made, should be made after firstconfirming that the spark plugs, the injectors, the idlespeed control servo, the compression pressure, etc.,are all normal.
1. Before inspection and adjustment, set the vehicle to thepre-inspection condition.
2. Connect the MUT-II to the diagnosis connector (16-pin).
NOTEWhen the MUT-II is connected, the diagnosis controlterminal should be earthed.
3. Start the engine and run at idle.
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13A FUEL MPI 1999 – On-vehicle Service
4. Select the item No. 30 of the MUT-II Actuator test.
NOTEThis holds the ISC servo at the basic step to adjust thebasic idle speed.
5. Check the idle speed.
Standard value:700 ± 50 r/min <Vehicles for Australia>
NOTE(1) The engine speed may be 20 to 100 r/min lower
than indicated above for a new vehicle [drivenapproximately 500 km or less], but no adjustmentis necessary.
(2) If the engine stalls or the engine speed is low eventhough the vehicle has been driven approximately500 km or more, it is probable that deposits areadhered to the throttle valve, so clean it.
6. If not within the standard value range, turn the speedadjusting screw (SAS) to make the necessary adjustment.
7. Press the MUT-II clear key, and release the ISC servofrom the Actuator test mode.
NOTEUnless the ISC servo is released, the Actuator test modewill continue 27 minutes.
8. Switch OFF the ignition switch.9. Disconnect the MUT-II.10. Start the engine again and let it run at idle speed for
about 10 minutes; check that the idling conditions isnormal.
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13A FUEL MPI 1999 – On-vehicle Service
COMPONENT LOCATION
Name Symbol
Purge control solenoid valve A
Idle speed control servo B
Air flow sensor (with intake air temperature sensor andbarometric pressure sensor)
C
A B C
INTAKE AIR TEMPERATURE SENSOR CHECKThe shape of the air flow sensor connector has been changed.The check procedure is the same as before.
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Equipment side connector
Air flow sensor
13A FUEL MPI 1999 – On-vehicle Service
IDLE SPEED CONTROL (ISC) SERVO(STEPPER MOTOR) CHECKChecking the Operation Sound1. Check that the engine coolant temperature is 20�C or
below.
NOTEDisconnecting the engine coolant temperature sensorconnector and connecting the harness-side of theconnector to another engine coolant temperature sensorthat is at 20�C or below is also okay.
2. Check that the operation sound of the stepper motorcan be heard after the ignition is switched ON. (but withoutstarting the motor.)
3. If the operation sound cannot be heard, check the steppermotor’s activation circuit.If the circuit is normal, it is probable that there is amalfunction of the stepper motor or of the engine controlunit.
Checking the Coil Resistance1. Disconnect the idle speed control servo connector.2. Measure the resistance between terminal 2 and either
terminal 1 or terminal 3 of the connector at the idle speedcontrol servo side.
Standard value: 28 – 33 � (at 20�C)
3. Measure the resistance between terminal 5 and eitherterminal 6 or terminal 4 of the connector at the idle speedcontrol servo side.
Standard value: 28 – 33 � (at 20�C)
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���Idle speedcontrol servo
13A FUEL MPI 1999 – On-vehicle Service
Operation Check1. Remove the throttle body.2. Remove the idle speed control servo.
3. Connect the special tool (test harness set: MB991709)to the idle speed control servo connector.
4. Connect the positive (+) terminal of a power supply(approx. 6 V) to the terminals No. 2 and No. 5.
5. Hold the ISC servo as shown in the illustration. Connectthe negative (–) terminal of the power supply to eachclip as described in the following steps, and check whetheror not a vibrating feeling (a feeling of very slight vibrationof the stepper motor) is generated as a result of theactivation of the stepper motor.
(1) Connect the negative (–) terminal of the power supplyto the terminals No. 1 and No. 4.
(2) Connect the negative (–) terminal of the power supplyto the terminals No. 3 and No. 4.
(3) Connect the negative (–) terminal of the power supplyto the terminals No. 3 and No. 6.
(4) Connect the negative (–) terminal of the power supplyto the terminals No. 1 and No. 6.
(5) Connect the negative (–) terminal of the power supplyto the terminals No. 1 and No. 4.
(6) Repeat the tests in sequence from (5) to (1).
6. If, as a result of these tests, vibration is detected, thestepper motor can be considered to be normal.
PURGE CONTROL SOLENOID VALVE CHECKRefer – Emission Control System.
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13A FUEL MPI 1999 – Throttle Body
THROTTLE BODYDISASSEMBLY AND REASSEMBLY
6
2
4
1
5
3
Disassembly steps��� 1. Throttle position sensor
2. Idle speed control servo3. O-ring4. Throttle body5. Speed adjusting screw6. O-ring
NOTE1. The speed adjusting screw is correctly adjusted at the
factory and should not be removed.2. If the speed adjusting screw has been removed, carry
out fixed SAS adjustment.3. If the speed adjusting screw should happen to have been
removed, carry out speed adjusting screw adjustment.
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13A FUEL MPI 1999 – Throttle Body
CLEANING THROTTLE BODY PARTS(1) Clean all throttle body parts.
Do not use solvent to clean the following parts:� Throttle position sensor� Accelerator pedal position sensor� Idle speed control body assemblyIf these parts are immersed in solvent, their insulationwill deteriorate.Wipe them with cloth only.
(2) Check if the vacuum port of passage is clogged. Usecompressed air to clean the vacuum passage.
REASSEMBLY SERVICE POINTS�A� THROTTLE POSITION SENSOR (TPS)
INSTALLATION(1) Place the throttle position sensor against the throttle body
as shown by the dotted line in the illustration.(2) Turn the throttle position sensor to the position shown
in the illustration, and then tighten the screw.
(3) Connect a multimeter between terminal (4) (TPS powersupply) and terminal (3) (TPS output) of the TPSconnector, and check that the resistance increasesgradually as the throttle valve is opened slowly to thefully-open position.
(4) If there is an abnormality, replace the TPS.
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Throttle position sensor
TPS output
Earth TPS power supply
No connection
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