man injectie electronica edc m.s 6.4

T 17-A2 8.40 - 1

DIAGNOSIS Fault search programme The following error search programme contains the errors that can be detected by the error memory. The order of the tests corresponds to the numeric sequence of the flash codes, independent of the value of the error. So it is not arranged according to "Error is displayed by means of EDC indicator light" or "Error is not displayed by means of EDC indicator light". In addition to the flash code, the error location was recorded in hexadecimal figures, because this is displayed by MAN-cats. During the initial check on the vehicle, the entire error memory must always be read out and all the stored errors documented. A simple method of documentation is to make a screen copy (hardcopy) of the MAN-cats screen. This contains all the information (environmental conditions, etc.). This is important because during error search cables or components in the system have to be disconnected and there should be the capability of setting and storing the corresponding error messages. Because of this, the error memory should always be deleted again after intermediate tests. The test procedure for checking cables ("Test lines") must always be followed: Interruption or contact resistance (e.g. through stretched terminal sockets, plugs or terminal sockets

pushed back, or oxidised plug connections)

Short to minus

Short to plus

Short to adjacent wires

Loose contacts

Water or moisture in the wiring harness

Wiring harnesses can also be damaged although the corrugated tube appears undamaged externally! All tests relating to the control device plugs are carried out with the aid of the diagnostic connector box (test box). The pin assignment on the control unit plug is identical to the test sockets on the diagnostic connector box. Where resistances are being measured, the control unit must be disconnected at the diagnostic connector box. Before any exchange of pump or control units the error memory should always be deleted and the error observed. If there are a number of error entries, the corresponding test instructions should generally only be taken into account where they do not require a change of pump or control unit. After removal of the error and checking, repeat the test and delete the error memory. The error memory should always be deleted with MAN-cats.

Follow vehicle-related wiring diagrams!

In the case of bus chassis (HOC) 3-character wire numbers and deviating item descriptions are mainly used. On all other vehicles in the present series (trucks and buses) only 5-character wire numbers and identical item descriptions are used.

T 17-A2 8.40 - 3

DIAGNOSIS TEST 1

Pedal sensor Flash code: 1x short Error location (hex): 81 Error display: Yes (indicator light EDC on, or shown in display) Error path: Pedal sensor – Signal too high – Signal too low Effect of error: Torque reduced by 50 – 60% Default 50% Possible Interruption on line, short-circuit, interruption in power supply, cause of error: Pedal sensor faulty, control unit faulty Condition for testing: Diagnostics connector box (test box) connected Ignition switched on Follow vehicle-related wiring diagrams! Test Measurement Remedy

Power supply Voltage measurement at diagnostics connectors (test box) between Pin B16 (+) and Pin B35 (–)

Target value: 4.5 – 5.2 V

− Test lines

− Test plug connectors

− If not fault found, try replacing the control unit

Potentiometer signal Voltage measurement at diagnostics connectors (test box) between Pin B23 (+) and Pin B35 (–)

Target values: Idle speed: 0.3 – 0.6 V Full-load: 4.0 – 4.5 V

Error limits: U < 0.3 V or U > 4.8 V

− Test lines


− Adjust linkage between accelerator pedal and pedal sensor

− If adjustment is not possible, replace pedal sensor

8.40 - 4 T 17-A2

DIAGNOSIS TEST 2

Quantity solenoid valve for fuel injection pump (plausibility of actuation duration) Flash code 2x short Error location (hex): 82 Error display: Yes (indicator light EDC on, or shown in display) Error path: Actuation duration of the solenoid valve, quantity transferred on the CAN-bus to the pump Effect of error: Engine is shut down Engine does not start Possible cause of error: Power supply (Ubat/earth), injection pump faulty Note: Basically before replacing any pump or control unit the error memory should be

deleted and the error observed. In practice, where there are several error entries, the corresponding test

instructions should first be followed where they do not necessitate the exchange of a pump or control unit.

Follow vehicle-related wiring diagrams!

Test Measurement Remedy

Injection pump

Voltage measurement between Pin 7 (+) and Pin 6 (–) at injection pump plug

Target value: UBat

− Test lines


− Reprogram control unit to latest status

− If fault is still present, try replacing the injection pump*

* Fitting and removing the injection pump and carrying out the associated adjustments is described in the repair manual for the A 14!

T 17-A2 8.40 - 5

DIAGNOSIS TEST 3

Engine speed sensor (flywheel) Flash code 4x short Error location (hex): 84 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine speed sensor – Static: implausible – Dynamic: implausible Effect of error: Full load quantity reduced by 25 – 40% Final engine speed reduced to 1800 rpm The system switches from injection start control to control mode with prescribed injection start characteristic map; the engine is shut down if there are deviations are found in comparison with the pump speed sensor Possible Line interruption, short to earth, speed sensor faulty cause of error: Sensor signal affected by metal filings, etc. at sensor's mounting position Distance from speed sensor to flywheel is incorrect, wrong flywheel Control unit faulty Condition for testing: Diagnostics connector box (test box) connected Note: This error can simultaneously arise with error 5x long, 1x short (speed sensor

signal detection – pump control unit) Follow vehicle-related wiring diagrams!


Resistance Resistance measurement at diagnostics connectors (test box) between Pin A1 (+) and Pin A13 (–)

Target value: 770 – 1000 Ω

− Test lines


− If no fault can be found, replace engine speed sensor

Engine speed signal Signal test at diagnostics connector box (test box) with starting rpm between Pin A1 (+) and Pin A13 (–) with oscilloscope

Target value: see oscilloscope curves

− Test lines


− If no fault can be found, replace control unit

Gap between engine sped sensor and flywheel

Target value: 0.5 – 1.5 mm − Correct gap

8.40 - 6 T 17-A2

DIAGNOSIS TEST 4

Charge air pressure sensor Flash code 5x short Error location (hex): 85 Error display: Yes (indicator light EDC on, or shown in display) Error path: Charge air pressure sensor – Signal too high – Signal too low – Signal implausible in combination with atmospheric pressure sensor (in control unit) Effect of error: Full-load quantity reduced by 20 – 40%, default 1200 mbar Black smoke during acceleration sequences Possible interruption on line, short-circuit, intake manifold pressure sensor faulty, cause of error: intake manifold connection leak, atmospheric pressure sensor (in control unit) faulty, control unit faulty Condition for testing: Diagnostics connector box (test box) connected Ignition switched on Application of pressure by pressure sensor with ALDA test device or Mitywac Duo-

hand pump (absolute pressure gauge) Follow vehicle-related wiring diagrams! Test Measurement Remedy

Power supply Voltage measurement at diagnostics connectors (test box) between Pin A23 (+) and Pin A17 (–)

Target value: 4.75 – 5.25 V

− Test lines



Signal voltage Voltage measurement at diagnostics connectors (test box) between Pin A12 (+) and Pin A17 (–)

Target values: 1.50 – 1.70 V at 1500 mbar 2.70 – 3.00 V at 2000 mbar


− Test lines


− If no fault can be found, replace intake manifold pressure sensor

Characteristic curve with 5 V supply

Note: Absolute pressures are used in the above diagram!

T 17-A2 8.40 - 7

DIAGNOSIS TEST 5

Temperature sensor, coolant

Flash code 7x short Error location (hex): 87 Error display: Yes (indicator light EDC on, or shown in display) Error path: Temperature sensor, coolant Effect of error: Full load quantity reduced by 50% Formation of a default value (approx. 110 °C) Worse cold start performance Possible cause of error: Interruption on line, short-circuit, temperature sensor faulty, control unit faulty Condition for testing: Diagnostics connector box (test box) connected Follow vehicle-related wiring diagrams!


Sensor resistance Resistance measurement at diagnostics connector box (test box) between Pin A22 and Pin A5 Target values: 3.6 – 1.3 KΩ at 15 – 30 °C 460 – 230 Ω at 75 – 80 °C

− Test lines


− Replace temperature sensor


Sensor voltage Voltage measurement at diagnostics connectors (test box) between Pin A22 and Pin A5 Target value: 3.0 – 1.15 V at 30 – 90 °C


− Test lines


− Replace temperature sensor


8.40 - 8 T 17-A2

DIAGNOSIS TEST 6

Road speed signal Flash code 8x short Error location (hex): 88 Error display: Yes (indicator light EDC on, or shown in display) Error path: Road speed transducer – Signal too high – Signal too low – No signal – Frequency too high Effect of error: All speed functions such as cruise control ("Tempomat"), speed control and

maximum speed limiter are shut down No idle speed comparison Possible Interruption of line, plug connector in flexible steel-armoured cable is oxidising cause of error: (ingress of water), short circuit, tachograph faulty Condition for testing: Diagnostics connector box (test box) connected Follow vehicle-related wiring diagrams!


Signal line Resistance measurement at diagnostics connector box (test box) between Pin B29 and tachograph Kl. B7 Target value: 0 Ω

− Test lines


− If no fault can be found, try replacing tachograph

Voltage measurement at diagnostics connectors (test box) between Pin B29 and Pin B2 Target value: > 0.6 V

T 17-A2 8.40 - 9

DIAGNOSIS TEST 7

Pump control unit self-test (pump characteristic map not present) Flash code 9x short Error location (hex): 89 Error display: Yes (indicator light EDC on, or shown in display) Error path: Pump control unit (pump characteristic map not present) Effect of error: Engine does not start Possible cause of error: Pump control unit (injection pump) faulty Note: Basically before replacing any pump or control unit the error memory should be deleted and the error observed. In practice, where there are several error entries, the corresponding test instructions should first be followed where they do not necessitate the exchange of a pump or control unit.


Injection pump – – – − Delete error memory

− Read error memory again

− If fault still present, try replacing injection pump* * Fitting and removing the injection pump and carrying out the associated adjustments is described in the repair manuals for the A 13 and A 14!

8.40 - 10 T 17-A2

DIAGNOSIS TEST 8

Shutdown via quantity 0 (after-running test) Flash code 1x long, 2x short Error location (hex): 92 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine control unit, vehicle speed signal, injection pump Effect of error: Full-load quantity reduced by 25 – 40% because quantity can be inaccurate Final engine speed reduced to 2200 rpm

Function: Quantity 0 is the default for after-running. If the expected fall in speed does not come about, it is classified as an error. Possible cause of error: Engine control unit faulty, vehicle speed signal implausible, injection pump faulty Note 1: Basically before replacing any pump or control unit the error memory should be deleted and the error observed. In practice, where there are several error entries, the corresponding test instructions should first be followed where they do not necessitate the exchange of a pump or control unit. Note 2: In the event of errors in after-running, the road speed signal must also be checked. Reason: If the road speed transducer already shows 0 km/h when the vehicle is

rolling and the ignition is then switched off, there is after-running. The various shutdown paths in after-running can then be classified as defective

because the speed does not drop away fast enough (vehicle is rolling). Follow vehicle-related wiring diagrams! Test Measurement Remedy

Engine control unit

Vehicle remains standing, speed is 800 rpm, multiple starting of engine (7 times) to delete error Minimal engine standstill period 5 s between attempts at starting

− Delete error memory

− Read error memory once again

− If no fault can be found, replace engine control unit



− If no fault can be found, replace injection pump*

Road speed signal

See test 6 − See test 6

* Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

T 17-A2 8.40 - 11

DIAGNOSIS TEST 9

Undervoltage Flash code: 1x long, 3x short Error location (hex): 13 Error display: No (indicator light EDC off, or nothing shown in display) Error path: Power supply for control unit (battery voltage too low < 9 V) Effect of error: Depending on the amount of the drop in voltage, the EDC system or engine may

react in various ways: – engine does not start – engine runs very out of true – no output – high degree of smoke – contradictory error memory input Possible Battery discharged or faulty, generator faulty, interruption in line, short circuit, cause of error: main relay faulty Condition for testing: Diagnostics connector box (test box) connected Ignition switched on Follow vehicle-related wiring diagrams Test Measurement Remedy

Power supply Voltage measurement at diagnostics connectors (test box) between Pin B15 (+) and Pin B1 (–) Pin B15 (+) and Pin B27 (–) Pin B3 (+) and Pin B2 (–) Pin B4 (+) and Pin B1 (–) Target value: 20 – 28 V

− Test lines


− Replace main relay


8.40 - 12 T 17-A2

DIAGNOSIS TEST 10

Proximity switch, brake Flash code: 1x long, 4x short Error location (hex): 94 Error display: No (indicator light EDC off, or nothing shown in display) Error path: Proximity switch, brake signal Effect of error: FGR and ZDR not functioning Possible cause of error: Interruption in line, proximity switch faulty or wrongly calibrated Condition for testing: Diagnostics connector box (test box) connected Ignition switched on Follow vehicle-related wiring diagrams


Proximity switch brake signal

Voltage measurement at diagnostics connectors (test box) between Pin B26 (+) and Pin B2 (–) Brake pedal actuated

Target value: UBat

Brake pedal not actuated

Target value: 0 – 2 V

− Test lines


− Adjust proximity switch

− Replace proximity switch

T 17-A2 8.40 - 13

DIAGNOSIS TEST 11

Proximity switch, clutch Flash code: 1x long, 5x short Error location (hex): 15 Error display: Yes (indicator light EDC on, or shown in display) Error path: Proximity switch, clutch signal Effect of error: ZDR not functioning Possible Interruption to line, proximity switch faulty cause of error: The control unit also detects errors if a speed of 30 km/h is exceeded and by then still no clutch signal has been detected Condition for testing: Diagnostics connector box (test box) connected Ignition switched on Follow vehicle-related wiring diagrams


Proximity switch for clutch signal

Voltage measurement at diagnostics connectors (test box) between Pin B20 (+) and Pin B2 (–) Clutch pedal actuated

Target value: UBat

Clutch pedal not actuated

Target value: 0 – 2 V

− Test lines


− Adjust proximity switch

− Replace proximity switch

8.40 - 14 T 17-A2

DIAGNOSIS TEST 12

Overspeed Flash code: 1x long, 7x short Error location (hex): 17 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine overspeed Effect of error: Interruption in delivery of volume. If there are not further errors, delivery will resume after quitting the overspeed. Possible cause of error: Incorrect operation, driver error (e.g. bad gearshift)


– – – If not other error present no further actions are necessary

Delete error memory

T 17-A2 8.40 - 15

DIADNOSE TEST 13

Injection start deviation

Flash code: 1x long, 8x short Error location (hex): 18 Error display: Yes (indicator light EDC on, or shown in display) Error path: Injection start actuator unit, deviation Effect of error: Full load quantity reduced by 50 – 60% Final engine speed reduced to 1700 rpm Strong smoke development The system switched from closed-loop control to open-loop control with a

predetermined injection start characteristic. Possible Fault in fuel system (leak, clogged, air in system) cause of error: – Faulty or wrong overflow valve in pump's intake or return – Pre-delivery pump faulty – Empty tank – Tank ventilation faulty – Fuel filter defective (can result in pump contamination) Speed transducer signals incorrect Needle movement sensor signals incorrect (omitted from level 2 onwards) Basic configuration of pump is false Injection pump defective Note: The function paths needle movement sensor (omitted from level 2 onwards) and

speed sensor (flywheel and injection pump) must always be checked in the case of this fault, even if there is no relevant error entered in the memory.

Follow the wiring diagrams relating to the vehicle.


Injection pump Target value and actual value Check injection start

Error condition: +/– 3 degrees deviation, 2.5 s monitoring only if engine speed > 1000 rpm

− Test fuel system

− Test lines


− Test pump installation*

− Replace injection pump*

Needle movement sensor

See test 14 See test 14

Engine speed sensor See test 3 See test 3 * Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

8.40 - 16 T 17-A2

DIAGNOSIS TEST 14

Needle movement sensor Flash code: 1x long, 10x short Error location (hex): 1A Error display: No (indicator light EDC off, or nothing shown in display) Error path: Needle movement sensor – Signal not high enough – too few impulses – too many impulses – internal resistance wrong Effect of error: The system switches from closed-loop control to controlling the start of delivery.

If the fault is no longer present, the system switches back to normal closed-loop control.

Possible cause of error: Interruption on line, short-circuit, needle movement sensor faulty Note: The needle movement sensor becomes obsolete with the introduction of

EDC 6.4 level 2! Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle.


Internal resistance

Resistance measurement at diagnostics connector box (test box) between Pin A29 and Pin A15 Target values: 65 – 160 Ω See oscilloscope curves

− Test lines


− Replace needle movement sensor

Other possible causes of errors: − Faulty impulses from the speed sensor (even without error message) − Spurious pulses between the control unit and needle movement sensor (e.g. through relay switching) − Structure-borne noise effect on needle movement sensor through mechanical damage (e.g. valve train,

piston) − Jet needle sticking Fault in fuel low-pressure system

− Faulty or wrong overflow valve − Air or leaks in the system − Faulty fuel pump − Clogged filter − Clogged lines − Empty fuel tank − Faulty injection pump

T 17-A2 8.40 - 17

DIAGNOSIS TEST 15

Plausibility of solenoid valve shutdown (MAB signal) Flash code: 1x long, 11x short Error location (hex): 9B Error display: Yes (indicator light EDC on, or shown in display) Error path: Status of solenoid valve shutdown Effect of error: Full load quantity reduced by 25 – 40% Final engine speed reduced to 2200 rpm

Shutdown might not be possible via MAB Function: Check whether MAB status is the same in the pump control unit and the engine control unit Possible Line interruption between engine control unit and injection pump cause of error: (pump control unit), engine control unit faulty, injection pump (pump control unit) faulty Note: Before any exchange of pump or control units the error memory should always be

deleted and the error observed. If there are a number of error entries, the corresponding test instructions should

generally only be taken into account where they do not require a change of pump or control unit.

Follow vehicle-related wiring diagrams Test Measurement Remedy

Engine control unit

Voltage measurement at diagnostics connectors (test box) between Pin B3 and Pin A20 Target value: UBat with ignition on 0 V with ignition off

− Test lines




− If fault still present, try replacing the engine control unit



− If fault still present, try replacing the injection pump*


8.40 - 18 T 17-A2

DIAGNOSIS TEST 16

Multi-level switch (resistor group) torque limiter Flash code: 1x long, 12x short Error location (hex): 1C Error display: No (indicator light EDC off, or nothing shown in display) Error path: Multi-level switch (resistor group) torque limiters – voltage too high – voltage too low – wrong voltage Effect of error: No multilevel switch functions are possible Function: Voltage signals are detected via the multilevel input (control unit pin B28), whose

values are determined by external resistance circuits. The limits can be programmed with MAN-cats. Possible cause of error: Line interruption, short circuit, resistor group faulty (e.g. cold junction) Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

Resistor group Voltage measurement at diagnostics connector box (test box) between Pin B28 and Pin B35 Target values: Handling characteristics: 0.75 – 1.25 V (resistance R 5 = 0.511 kΩ) Torque limiter: 1.75 – 2.25 V (resistance R 6 = 1.37 kΩ) Retarder active: 2.75 – 3.25 V (resistance R 7 = 3.09 kΩ) Speed limiter with special application: 3.75 – 4.25 V (resistance R 8 = 8.20 kΩ)

− Test lines


− Replace resistor group

− If no fault found, try replacing the control unit

T 17-A2 8.40 - 19

DIAGNOSIS TEST 17

Operating unit (combination switch on steering column) Flash code: 1x long, 13x short Error location (hex): 1D Error display: Yes (indicator light EDC on, or shown in display) Error path: Operating unit (combination switch on steering column) faulty – Voltages false or implausible EOL programming faulty Effect of error: The cruise control is not functioning. Simultaneously all further functions of the

operating unit such as intermediate speed control or idle speed control are not longer capable of activation.

If the fault was only temporary (e.g. through multiple activation of the operating unit) the system will become operable again after switching the ignition off and then on again.

Function: The operating unit is resistance-coded, in other words the control unit recognises

every switching state by reference to the voltage that has been read in. It recognises an error if the wrong values are output over a certain period, e.g. through electrical faults but also through multiple activation (incorrect operation!) of the operating unit.

Possible cause of error: Interruption on line, short-circuit, operating unit faulty, EOL programming wrong Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle.


Operating unit

Voltage measurement at diagnostics connector box (test box) between Pin B8 and Pin B9 Switch on all switch positions of opreating unit determine the voltages Target values: SET+ 0.83 – 1.21 V SET– 2.53 – 2.97 V MEMORY 1.60 – 2.00 V AUS (OFF) 4.18 – 4.53 V Not activated 3.35 – 3.74 V

− Test lines


− Test EOL programming

− Replace operating unit

− If no fault can be found, try replacing control unit

8.40 - 20 T 17-A2

DIAGNOSIS TEST 18

PBM interface (DKR/DKV) Flash code: 1x long, 14x short Error location (hex): 1E Error display: No (indicator light EDC off, or nothing shown in display) Error path: PWM = Pulse-width-modulated signal Control unit input Pin B30 (DKR) and Pin B7 (DKV) – faulty – interrupted EOL programming faulty Effect of error: No intervention in quantity possible through PBM interface (e.g. ASR) No load-dependent gear changes (automatic transmission) possible Possible cause of error: Short to minus, line interruption, EOL programming wrong Note 1: If the DKR line is interrupted (e.g. faulty control switch for ASR shutdown) then no

DKV signal is emitted Note 2: The PWM interface is only active with partner systems without CAN Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow the wiring diagrams relating to the vehicle.


Lines to the partner system

Resistance measurement at diagnostics connector box (test box) between Pin B7 and Pin B1/B2 Target value: ∞ Ω

− Test line (including partner systems)

− Test plug connector


Lines to the partner system

Resistance measurement at diagnostics connector box (test box) between Pin B30 and Pin B1/B2 Target value: ∞ Ω

− Test line (including partner systems)

− Test plug connector

− If lines OK, continue fault search in partner system

T 17-A2 8.40 - 21

DIAGNOSIS TEST 19

CAN 1 interface (ASR, GS, FM) Flash code: 1x long, 15x short Error location (hex): 1F Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine control unit Effect of error: Data exchange between the EDC system and the connected electronic systems is

interrupted Possible Interface error cause of error: EOL programming wrong Control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

Control unit Resistance measurement at diagnostics connector box between Pin B11 and Pin B12 Target value: ∼ 120 Ω

Error condition: 5 s no message received

− Test lines


− At ca. 0 Ω short-circuit from CAN-H to CAN-L

− Try replacing control unit

8.40 - 22 T 17-A2

DIAGNOSIS TEST 20

Timeout: CAN signal ASR

Flash code: 2x long, 1x short Error location (hex): 21 Error display: No (indicator light EDC off, or nothing shown in display) Error path: CAN signal from ABS/ASR control unit faulty Effect of error: ASR not functioning Possible cause of error: Line interruption, short-circuit, wrong EOL programming of the ABS control unit Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

EDC control unit Resistance measurement at diagnostics connector box between Pin B11 and Pin B12 Target value: ∼ 120 Ω

Error condition: Timeout period 5 s

− Test lines



− Try replacing control unit

ABS/ASR control unit Resistance measurement between Pin X1/3 and Pin X1/1 Target value: 60 Ω

− Test lines



− At ca. 120 Ω the connection to the terminator is broken


T 17-A2 8.40 - 23

DIAGNOSIS TEST 21

Shutdown via relay redundant shutdown MAR (after-running test) Flash code: 2x long, 2x short Error location (hex): A2 Error display: Yes (indicator light EDC on, or shown in display) Error path: Relay, redundant shutdown (MAR), engine control unit Effect of error: Full load quantity reduced by 25 – 40% Final engine speed reduced to 2200 rpm

Engine shutdown via MAR (relay redundant shutdown) impossible Function: The relay redundant shutdown (MAR = solenoid valve shutdown relay) is actuated

by the engine control unit (pin B18) and in the individual case interrupts the power supply to the pump control unit.

This leads to shutdown of the engine. In after-running the MAR is shut down (de-energised). If the expected fall in speed

does not come about, it is classified as an error. Possible Line interruption, short-circuit, relay redundant shutdown (MAR) faulty, actuation cause of error: from control unit faulty (engine control unit faulty), road speed signal implausible Note: In the event of errors in after-running, the road speed signal must also be checked. Reason: If the road speed transducer already shows 0 km/h when the vehicle is


because the speed does not drop away fast enough (vehicle is rolling). Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams


Pump relay (MAR)

Start engine and run at idling speed. Pull bridge Pin B18 at diagnostics connector box (test box). Engine must shut down within 3 s

− Test lines


− Replace relay

Power supply MAR Switch on ignition Voltage measurement at diagnostics connector box (test box) between Pin B18 and B2

Target value: UBat Switch off ignition Voltage measurement at diagnostics connector box (test box) between Pin B18 and B2

Target value: 0 V

− Test lines


− If not fault can be found, replace the control unit

Road speed signal See test 6 − See test 6

8.40 - 24 T 17-A2

DIAGNOSIS TEST 22

Timeout: CAN signal, transmission to EDC

Flash code: 2x long, 3x short Error location (hex): 23 Error display: No (indicator light EDC off, or nothing shown in display) Error path: CAN signal from transmission control unit faulty Effect of error: Restriction of functioning of transmission control Possible Interface error cause of error: Line interruption, short-circuit Control unit faulty EOL programming wrong Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

EDC control unit Resistance measurement at diagnostics connector box between Pin B11 and Pin B12 Target value: ∼ 120 Ω

Error condition: Timeout period 5 s

− Test lines



− Try replacing the control unit

T 17-A2 8.40 - 25

DIAGNOSIS TEST 23

Pedal sensor (plausibility with brake) Flash code: 2x long, 4x short Error location (hex): 24 Error display: No (indicator light EDC off, or nothing shown in display) Error path: Idle speed switch in pedal sensor – implausible to the brake signal Proximity switch, brake Effect of error: Speed diminishes to idling Function: This test is designed to check for a hanging or stuck accelerator pedal. In other

words, the accelerator pedal is not in or not completely in its idle position and simultaneously a brake signal is detected.

This situation can also be induced by simultaneous actuation of the brake and of the accelerator pedal.

Possible cause of error: Interruption on line, short-circuit, setting wrong, pedal sensor faulty, operator error Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Test 1 completed Follow the wiring diagrams relating to the vehicle.


Idle speed switch in pedal sensor See test 1 See test 1

Proximity switch, brake See test 10 See test 10

8.40 - 26 T 17-A2

DIAGNOSIS TEST 24

Main relay Flash code: 2x long, 5x short Error location (hex): 25 Error display: No (indicator light EDC off, or nothing shown in display) Error path: Main relay – Contact sticks or hangs (does not open) Effect of error: This fault may not be noticed Function: The minus-side actuation of the relay coil takes place through the control unit via

the control unit outlet pin B27. The main relay is de-energised with a time delay after switching off the ignition (after-running).

During after-running, various computer functions are checked and any faults detected are stored in the error memory.

Possible cause of error: Short circuit, main relay faulty Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle.


Main relay Voltage measurement at diagnostics connector box (test box) between Pin B27 and Pin B2 Target values: UBat with ignition off 0 V with ignition on

− Test lines


− If line is OK, replace main relay

T 17-A2 8.40 - 27

DIAGNOSIS TEST 25

Shutdown via monitoring module (after-running test) Flash code: 2x long, 6x short Error location (hex): A6 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine control unit, pump control unit (injection pump), road speed signal Effect of error: Full load quantity reduced by 25 – 40% Final engine speed reduced to 2200 rpm Shutdown via monitoring module impossible Function: Microprocessor is tested for functioning through question/answer routine. In after-running false responses are sent intentionally, so that they lead to the engine

shutting down. If the expected fall in speed does not come about, it is classified as an error. Possible Engine control unit faulty, pump control unit (injection pump) defective cause of error: Road speed signal implausible Note 1: Before any exchange of pump or control units the error memory should always be



Note 2: In the event of errors in after-running, the road speed signal must also be checked. Reason: If the road speed transducer already shows 0 km/h when the vehicle is


because the speed does not drop away fast enough (vehicle is rolling). Follow the wiring diagrams relating to the vehicle.


Engine control unit – – – − Delete error memory

− Read out error memory again

− If fault still present, repalce engine control unit

Pump control unit (injection pump)

– – – − Delete error memory

− Read out error memory again

− If fault still present, repalce engine injection pump*

Road speed signal See test 6 − See test 6 * Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

8.40 - 28 T 17-A2

DIAGNOSIS TEST 26

Atmospheric pressure sensor Flash code: 2x long, 8x short Error location (hex): A8 Error display: Yes (indicator light EDC on, or shown in display) Error path: Atmospheric pressure sensor in control unit faulty Effect of error: No direct effects In individual case there may simultaneously be an error message from the intake

manifold pressure sensor Possible cause of error: Atmospheric pressure sensor (control unit) faulty


Control unit If only this error is stored, no test is possible because the sensor is inside the control unit. However, if there is indication of a faulty intake manifold pressure sensor, this must first be put through test 4.

− Replace control unit

T 17-A2 8.40 - 29

DIAGNOSIS TEST 27

Solenoid valve for pump control unit Flash code: 2x long, 9x short Error location (hex): A9 Error display: Yes (indicator light EDC on, or shown in display) Error path: Fuel injection pump Effect of error: Final engine speed reduced to 2000 rpm Full load quantity reduced by 25 – 40% Engine is shut down Engine does not start Function: A failed output stage/short-circuit is diagnosed via measurement of voltage in pump

control unit Possible cause of error: Speed sensor on flywheel has a loose contact, injection pump defective Note: Before any exchange of pump or control units the error memory should always be



Follow vehicle-related wiring diagrams


Engine speed sensor



− Read error memory again

− If error still present, replace injection pump*


8.40 - 30 T 17-A2

DIAGNOSIS TEST 28

Timeout: CAN signal ASR to engine brake

Flash code: 2x long, 10x short Error location (hex): 2A Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from ABS/ASR control unit to engine brake Effect of error: ASR does not actuate the engine brake Possible cause of error: Interruption on line, short-circuit, control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams


EDC control unit See test 19 − See test 19

ABS/ASR control unit See test 20 − See test 20

T 17-A2 8.40 - 31

DIAGNOSIS TEST 29

Timeout: CAN signal transmission to engine brake

Flash code: 2x long, 11x short Error location (hex): 2B Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from transmission control to engine brake Effect of error: Transmission control does not actuate the engine brake Possible cause of error: Interruption on line, short-circuit, control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams



8.40 - 32 T 17-A2

DIAGNOSIS TEST 30

Timeout: CAN signal, vehicle management to engine brake

Flash code: 2x long, 12x short Error location (hex): 2C Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from vehicle management to engine brake Effect of error: Vehicle management does not actuate the engine brake Possible cause of error: Interruption on line, short-circuit, control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams



T 17-A2 8.40 - 33

DIAGNOSIS TEST 31

Timeout: CAN signal, vehicle management to EDC

Flash code: 2x long, 13x short Error location (hex): 2D Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from vehicle management to EDC Effect of error: No intervention in volume by vehicle management Possible cause of error: Interruption on line, short-circuit, control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams



8.40 - 34 T 17-A2

DIAGNOSIS TEST 32

Timeout: CAN signal transmission to EDC

Flash code: 2x long, 14x short Error location (hex): 2E Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from transmission to EDC Effect of error: No intervention in volume by transmission Possible cause of error: Interruption on line, short-circuit, control unit faulty Note: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams



T 17-A2 8.40 - 35

DIAGNOSIS TEST 33

After-running control Flash code: 3x long, 8x short Error location (hex): 38 Error display: Yes (indicator light EDC on, or shown in display) Error path: Control unit for actuation output faulty – Computer after-running has not taken place Effect of error: Final engine speed reduced to 2200 rpm Full load quantity reduced by 25 – 40% Function: After-running automatically takes place after each shutdown procedure Possible Power supply for control unit for after-running is not secured cause of error: EOL not completed Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

Power supply to control unit

Voltage measurement at diagnostics connector box (test box) between Pin B3/B4 and Pin B1/B2

Target values: UBat with ignition off as long as after-running takes place in control unit. Main battery switch is held by the EDC control unit (holding circuit)

Error condition: Relay must have responded within 5 s

− Test lines


− Test after-running circuit

− Test main relay

Oscilloscope measurement on switching ignition on and off

ON OFF

CH 1: Pin B1–B3 CH 1: Pin B1–B3 CH 2: Pin B15–B1 CH 2: Pin B15–B1 If Pin B1–B3 is live for 5 s longer than Pin B15–B1, there is a "main relay" fault classification

CH 2: 10.0 V 200 ms CH 1: 10.0 V 200 ms

CH 2: 10.0 V 200 ms CH 1: 10.0 V 200 ms

8.40 - 36 T 17-A2

DIAGNOSIS TEST 34

Pump control unit self-test: Solenoid valve voltage measurement Flash code: 4x long, 1x short Error location (hex): C1 Error display: Yes (indicator light EDC on, or shown in display) Error path: Pump control unit (injection pump) Effect of error: None known of Function: Monitoring of voltage in self-test if solenoid valve is not actuated Possible cause of error: Pump control unit (injection pump) faulty Note: Before any exchange of pump or control units the error memory should always be








T 17-A2 8.40 - 37

DIAGNOSIS TEST 35

Pump temperature (pump control unit) Flash code: 4x long, 2x short Error location (hex): 42 Error display: No (indicator light EDC off, or nothing shown in display) Error path: Injection pump (pump control unit) fuel temperature too high Effect of error: If the values are implausible there is a switch to substitute value (75 °C) Possible cause of error: Fuel temperature too high, sensor in pump defective, injection pump faulty Note: Before any exchange of pump or control units the error memory should always be




Injection pump Error limits: If implausible values t > 130 °C or t < –45 °C the substitute value is set





8.40 - 38 T 17-A2

DIAGNOSIS TEST 36

Busoff: CAN 2 signal Flash code: 4x long, 3x short Error location (hex): C3 Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal between pump control unit and engine control unit on switching on (busoff) Effect of error: Engine goes into fast idling (ca. 750 rpm), acceleration now impossible Possible cause of error: Interruption on line, short-circuit, control unit faulty, injection pump faulty Note: Before any exchange of pump or control units the error memory should always be



Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams


Engine control unit

Resistance measurement at diagnostics control box between Pin A27 and A24 Target value: ∼120 Ω

− Test lines


− At ca. 0 Ω short-ciruit from CAN-H to CAN-L

− If fault is still present, try replacing the control unit



− If fault is still present, try replacing the injection pump*


T 17-A2 8.40 - 39

DIAGNOSIS TEST 37

CAN 2 signal (interface) Flash code: 4x long, 4x short Error location (hex): C4 Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal to pump control unit on switching on Effect of error: Engine goes into fast idling (ca. 750 rpm), acceleration now impossible Possible cause of error: Interface error Injection pump (pump control unit) faulty Note: Before any exchange of pump or control units the error memory should always be






− If fault still present, try replacing the injection pump* * Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

8.40 - 40 T 17-A2

DIAGNOSIS TEST 38

Shutdown via quantity solenoid valve (after-run test) Flash code: 4x long, 5x short Error location (hex): C5 Error display: Yes (indicator light EDC on, or shown in display) Error path: Status of solenoid valve shutdown (MAB) in after-running Effect of error: Final engine speed reduced to 2200 rpm Full load quantity reduced by 25 – 40%, impossible to shutdown engine via MAR (high-pressure solenoid valve in injection pump) Possible Actuation of control unit is faulty (engine control unit defective) cause of error: Injection pump (pump control unit) faulty Road speed signal implausible Note 1: Before any exchange of pump or control units the error memory should always be





because the speed does not drop away fast enough (vehicle is rolling). Condition for testing: Diagnostics connector box (test box) connected Follow vehicle-related wiring diagrams Test Measurement Remedy




Engine control unit See test 15 − See test 15


T 17-A2 8.40 - 41

DIAGNOSIS TEST 39

Busoff: CAN 1 signal Flash code: 4x long, 6x short Error location (hex): 46 Error display: Yes (indicator light EDC on, or shown in display) Error path: Vehicle CAN (busoff) Possible cause of error: Interruption on line, short-circuit, control unit faulty Note 1: Before any exchange of pump or control units the error memory should always be



Note 2: The CAN databus is described in the repair manual T 51 Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams


Engine control unit

Resistance measurement at diagnostics control box between Pin B11 and B12 Target value: ∼120 Ω

− Test lines



− Try replacing the control unit

8.40 - 42 T 17-A2

DIAGNOSIS TEST 40

Pump speed sensor (IWZ signal) Flash code: 4x long, 7x short Error location (hex): C7 Error display: Yes (indicator light EDC on, or shown in display) Error path: Fuel system Fuel injection pump Effect of error: Engine shuts down Function: Refer to page 3.02 - 14 Possible Fault in fuel system (leak, clogged, air in system) cause of error: Injection pump defective (dynamic: implausible, static; increments per segment not

complete) Note 1: Before any exchange of pump or control units the error memory should always be



Note 2: The fuel system layout (low pressure) is shown in the repair manuals A 13 and A 14.


Fuel system Fuel pressure − Vent (filter, then injector line at at least 3 injection nozzles)

− After successful start, leave engine idling for at least 30 s

− Fill the tank

Injection pump – – – − Test pump installation*



− If fault still present, try replacing the injection pump* * Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

T 17-A2 8.40 - 43

DIAGNOSIS TEST 41

Residual quantity Flash code: 4x long, 8x short Error location (hex): C8 Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal (quantity that is transferred to the pump on the CAN-bus) Effect of error: Engine stops because calculation of quantities inaccurate Function: If despite the quantity "quantity 0" being specified on the CAN the speed is

>700 rpm, the boost pressure >300 mbar and NBF signals (only with level 1) are detected, there is classification as an error

Possible Line interruption, short-circuit, control unit defective, NBF (only in level 1) faulty, cause of error: intake manifold pressure sensor faulty Note: Before any replacement of pump or control units the error memory should always

be deleted and the error observed. If there are a number of error entries, the corresponding test instructions should






Intake manifold pressure sensor


Needle movement sensor



8.40 - 44 T 17-A2

DIAGNOSIS TEST 42

Pump control unit self-test: solenoid valve output stage Flash code: 4x long, 9x short Error location (hex): C9 Error display: Yes (indicator light EDC on, or shown in display) Error path: Hardware error in solenoid valve output stage (pump control unit) Effect of error: None known of Function: Checking of output stage in PSG self-test Possible cause of error: Pump control unit (injection pump) faulty Note: Before any exchange of pump or control units the error memory should always be








T 17-A2 8.40 - 45

DIAGNOSIS TEST 43

Injection timing device (pump control unit) Flash code: 4x long, 10x short Error location (hex): CA Error display: Yes (indicator light EDC on, or shown in display) Error path: Target-actual value exceeding/not reaching injection timing device Effect of error: Final engine speed reduced to 1700 rpm Full load quantity reduced by 50 – 60% Possible Line interruption, short-circuit cause of error: Fault in fuel low-pressure system

– faulty or wrong overflow valve – air or leaks in the system – faulty pre-supply pump – blocked filters – clogged lines – empty fuel tank – faulty injection pump – faulty fuel filter

Note 1: Before any exchange of pump or control units the error memory should always be deleted and the error observed.

If there are a number of error entries, the corresponding test instructions should generally only be taken into account where they do not require a change of pump or control unit.

Note 2: The fuel pipework layout (low pressure) is shown in the repair manuals A 13 and A 14.


Injection pump Error condition: In case of deviation of target from actual value for injection start by more than +/– 3 grad longer than 8 s and speed > 1200 rpm




Fuel system Fuel pressure − See above (possible cause of error) * Fitting and removing the injection pump and carrying out the associated adjustments is described in repair manuals A 13 and A 14!

8.40 - 46 T 17-A2

DIAGNOSIS TEST 44

Timeout: CAN signal PSG 1 Flash code: 4x long, 11x short Error location (hex): CB Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from pump control unit to engine control unit (timeout) Effect of error: Engine goes into increased idling speed Possible cause of error: Line interruption, short-circuit, control unit faulty, injection pump faulty Note: Before any exchange of pump or control units the error memory should always be



Condition for testing: Diagnostics connector box (test box) connected Ignition switched off Follow vehicle-related wiring diagrams Test Measurement Remedy

Engine control unit


− Test lines








T 17-A2 8.40 - 47

DIAGNOSIS TEST 45

Shutdown via voltage monitoring (after-running test) Flash code: 4x long, 12x short Error location (hex): 99 Error display: Yes (indicator light EDC on, or shown in display) Error path: Status shutdown via voltage monitoring) Effect of error: Final engine speed reduced to 2200 rpm Torque reduced by 25 – 40%, shutdown via voltage monitoring impossible Function: In after-running, an error is consciously simulated (limit values). If the expected fall in

speed does not come about, it is classified as an error. Possible Line interruption between engine control unit and injection pump (pump control unit), cause of error: engine control unit faulty, injection pump (pump control unit) faulty If additionally the error "Plausibility shutdown signal (MAB)" or "Shutdown via

monitoring module" occurs, check MAB line. Note 1: Before any exchange of pump or control units the error memory should always be




rolling and the ignition is then switched off, there is after-running. The various shutdown paths in after-running can then be classified as defective because the speed does not drop away fast enough (vehicle is rolling).



Engine control unit



− If fault still present, try replacing the engine control unit

Pump control unit (injection pump)





8.40 - 48 T 17-A2

DIAGNOSIS TEST 46

Timeout: CAN signal MSG 1 Flash code: 4x long, 13x short Error location (hex): B1 Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal from engine control unit to pump control unit (timeout) Effect of error: Final engine speed reduced to 2000 rpm Torque reduced by 25 – 40% Possible cause of error: Line interruption, short-circuit, control unit faulty, injection pump faulty Note: Before any exchange of pump or control units the error memory should always be




Engine control unit


− Test lines








T 17-A2 8.40 - 49

DIAGNOSIS TEST 47

Supply voltage, pump control unit Flash code: 4x long, 14x short Error location (hex): B3 Error display: Yes (indicator light EDC on, or shown in display) Error path: Power supply to pump control unit, relay, redundant shutdown (MAR) Effect of error: Engine shuts down Engine does not start Possible cause of error: Line interruption, short-circuit Condition for testing: See below Follow vehicle-related wiring diagrams


Power supply Voltage measurement at cable loom plug to PSG between Pin 7 (+) and Pin 6 (–) Target value: UBat

Error limits: U < 7 V or U > 32 V

− Test line

− Test plug connection

Relay redundant shutdown (MAR)

Switch on ignition Voltage measurement at diagnostics connector box (test box) between Pin B18 and Pin B1 Target value: UBat

Switch off ignition Disconnect engine control unit Resistance measurement at diagnostics control box between Pin B18 and Pin B1 Target value: 180 – 250 Ω

− Test line

− Test plug

− Replace relay (MAR)

Plug for pump control unit

8.40 - 50 T 17-A2

DIAGNOSIS TEST 48

CAN signal, pump control unit (interface) Flash code: 4x long, 15x short Error location (hex): B4 Error display: Yes (indicator light EDC on, or shown in display) Error path: CAN signal to pump control unit (timeout value range violation) Effect of error: Engine goes into increased idling speed Engine shuts down Possible Line interruption, short-circuit, control unit faulty, injection pump faulty, cause of error: engine speed sensor flywheel faulty Note: Before any exchange of pump or control units the error memory should always be




Engine control unit Resistance measurement at diagnostics control box between Pin A27 and A24 Target value: ∼120 Ω

− Test lines



− If fault still present, try replacing control unit




Engine speed sensor



T 17-A2 8.40 - 51

DIAGNOSIS TEST 49

Speed sensor signal detection, pump control unit Flash code: 5x long, 1x short Error location (hex): B7 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine speed signal to the pump control unit Effect of error: Final engine speed reduced to 1800 rpm Torque reduced by 25 – 40% Function: Monitoring on negative flank in data collection window Possible Speed sensor flywheel faulty, sensor distance false (target: 0.5 – 1.5 mm). cause of error: Control unit faulty, injection pump installation wrong, injection pump faulty. "Injection start deviation" is sometimes displayed when there is a loose contact. The error "Speed sensor at flywheel" often appears at the same time Note: Before any exchange of pump or control units the error memory should always be




Engine speed sensor





Cables Line between Pin A35 engine control unit and Pin 8 pump control unit

− Test lines



8.40 - 52 T 17-A2

DIAGNOSIS TEST 50

Pump control unit self-test: EEPROM checksum Flash code: 5x long, 2x short Error location (hex): B5 Error display: Yes (indicator light EDC on, or shown in display) Error path: Checksum test EEPROM Effect of error: Final engine speed reduced to 1700 rpm Torque reduced by 50 – 60%, as injection timing device can go to advance stop Function: Checksum test in self-test Possible cause of error: Control unit faulty, pump control unit (injection pump) defective Note: Before any exchange of pump or control units the error memory should always be




Fuel injection pump





T 17-A2 8.40 - 53

DIAGNOSIS TEST 51

Pump control unit self-test: EEPROM status Flash code: 5x long, 3x short Error location (hex): B6 Error display: Yes (indicator light EDC on, or shown in display) Error path: Status check EEPROM (hardware error) Effect of error: Final engine speed reduced to 1700 rpm Torque reduced by 50 – 60%, as injection timing device can go to advance stop Function: Hardware check in self-test Possible cause of error: Control unit faulty, pump control unit (injection pump) defective Note: Before any exchange of pump or control units the error memory should always be




Fuel injection pump





8.40 - 54 T 17-A2

DIAGNOSIS TEST 52

Pump control unit self-test: ADC status Flash code: 5x long, 4x short Error location (hex): B2 Error display: Yes (indicator light EDC on, or shown in display) Error path: Status analog-digital converter Effect of error: Final engine speed reduced to 2000 rpm Torque reduced by 25 – 40% Function: In the self-test checking earth potential of a channel of the AD converter there is no

quantity correction Solenoid valve voltage is no longer acquired Possible cause of error: Control unit faulty, injection pump defective Note: Before any exchange of pump or control units the error memory should always be




Fuel injection pump





T 17-A2 8.40 - 55

DIAGNOSIS TEST 53

Pump control unit self-test: RAM Flash code: 5x long, 5x short Error location (hex): B9 Error display: Yes (indicator light EDC on, or shown in display) Error path: RAM in pump control unit Effect of error: Engine does not start Function: Checking RAM in self-test Possible cause of error: Control unit faulty, injection pump defective Note: Before any exchange of pump or control units the error memory should always be




Fuel injection pump





8.40 - 56 T 17-A2

DIAGNOSIS TEST 54

Polarity reversal, speed sensor on flywheel Flash code: 5x long, 6x short Error location (hex): 91 Error display: Yes (indicator light EDC on, or shown in display) Error path: Speed sensor on flywheel Effect of error: Final engine speed reduced to 1800 rpm Torque reduced by 25 – 40% Possible cause of error: Cable plugged in wrongly, fault in speed sensor Follow vehicle-related wiring diagrams


Cables Plug connection X337 X337 Pin e: cable colour white/blue X337 Pin F: cable colour blue Engine control unit Pin A1: cable colour white/blue Pin A13: cable colour blue

Error condition: Lower speed threshold: 500 rpm Upper speed threshold: 1500 rpm

− Cable should be assigned correctly

− If fault still present, try replacing the speed sensor

T 17-A2 8.40 - 57

DIAGNOSIS TEST 55

Engine control unit monitoring module (µµµµ-controller) Flash code: 5x long, 7x short Error location (hex): 96 Error display: Yes (indicator light EDC on, or shown in display) Error path: µ-Controller in engine control unit Effect of error: Engine shuts down Possible cause of error: Control unit faulty Note: Before any exchange of pump or control units the error memory should always be




Control unit – – – − Delete error memory


− If fault still present, try replacing the control unit

8.40 - 58 T 17-A2

DIAGNOSIS TEST 56

Pump control unit initialisation Flash code: 5x long, 8x short Error location (hex): CD Error display: Yes (indicator light EDC on, or shown in display) Error path: Exchange of messages between pump control unit and engine control unit takes too long Effect of error: Final engine speed reduced to 2000 rpm Torque reduced by 25 – 40% Function: In the self-test the exchange of messages between the pump control unit and engine

control unit is monitored for duration. If the time interval is too long, there is an error classification.

Possible Pump control unit (injection pump) faulty cause of error: CAN bus between engine control unit and pump control unit is defective Note: Before any exchange of pump or control units the error memory should always be




Fuel injection pump





T 17-A2 8.40 - 59

DIAGNOSIS TEST 57

Multi-level switch (resistor group), maximum speed limiter Flash code: 6x long, 6x short Error location (hex): DB Error display: Yes (indicator light EDC on, or shown in display) Error path: Multi-level switch (resistor group) for maximum speed limiters – voltage too high – voltage too low – wrong voltage Effect of error: No multilevel switch functions are possible Function: Voltage signals are detected via the multilevel inputs (control unit pin B19), whose

values are determined by external resistance circuits. The limits (HGB 1, 2 and 3) can be programmed with MAN-cats.

Possible cause of error: Line interruption, short circuit, resistor group faulty (e.g. cold junction) Note 1: The maximum speed limiters via the multilevel switch (control unit pin B19) are only

implemented from level 2 onwards. In level 1, HGB 2 is activated by wiring pin B21 with UBat. HGB 3 is not possible with level 1. Note 2: Activation of another maximum speed limit (e.g. by a changeover switch) is only

possible at below a road speed of 10 km/h! Condition for testing: Diagnostics connector box (test box) connected Follow the wiring diagrams relating to the vehicle. Test Measurement Remedy

Resistor group Voltage measurement at diagnostics connector box (test box) between Pin B19 and Pin B35 Target values: Maximum speed limit 1: 0.75 – 1.25 V (resistance R 1, 0.511 kΩ) Maximum speed limit 2: 1.75 – 2.25 V (resistance R 2, 1.37 kΩ) Maximum speed limit 3: 2.75 – 3.25 V (resistance R 3, 3.09 kΩ)

− Test lines

− Test plug-in connections

− Replace resistor group

− If no fault is found, try replacing the control unit

8.40 - 60 T 17-A2

DIAGNOSIS TEST 58

Error when sending a CAN message Flash code: 6x long, 11x short Error location (hex): E0 Error display: Yes (indicator light EDC on, or shown in display) Error path: Engine control unit Effect of error: None known of Possible cause of error: CAN from engine control unit faulty


Control unit See Test 19 − See Test 19

T 17-A2 8.40 - 61

DIAGNOSIS TEST 59

Test on shutdown paths Flash code: 6x long, 12x short Error location (hex): E1 Error display: Yes (indicator light EDC on, or shown in display) Error path: Road speed signal Effect of error: None known of Function: After-running automatically takes place after each shutdown When the permissible number of shutdowns has been exceeded without after-

running, it is classified as an error Possible cause of error: Road speed signal faulty Note: In the event of errors in after-running, the road speed signal must also be checked. Reason: If the road speed transducer already shows 0 km/h when the vehicle is

rolling and the ignition is then switched off, there is after-running. The various shutdown paths in after-running can then be classified as defective because the speed does not drop away fast enough (vehicle is rolling).



Road speed signal See Test 6 See Test 6

8.40 - 62 T 17-A2

DIAGNOSIS TEST 57

Engine brake Flash code: No data acquisition Error location (hex): No data acquisition Error display: No data acquisition Error path: Engine brake, engine brake switch Effect of error: No engine brake function Function: The engine brake is actuated corresponding to the engine speed via Pin A18

(output) of the EDC control unit. Actuation takes place by supplying current to Pin B14 (input) of the EDC control unit by actuation of the foot control switch for the engine brake. Actuation can also take place from the transmission control or vehicle management through a CAN message.

Possible cause of error: Line interruption, short-circuit, engine brake switch faulty Condition for testing: Diagnostics connector box (test box) connected Note 1: The engine brake function can also be switched off by other systems, e.g. by the

ABS control unit during a braking controlled under ABS. For this reasons the ABS system should be included when fault finding.

A clutch signal coming from a faulty or incorrectly adjusted proximity switch can also lead to failure of the engine brake.

Note 2: On part of the EDC control units 6.4 level 1 the engine braking activation functions

by the "flip-flop" principle, i.e. when the engine brake is actuated at a speed of >800 rpm, the engine brake stays active even though the control switch is no longer actuated. Only when the foot control switch is activated again or the brake, clutch or accelerator pedal are operated is the engine brake deactivated.

During EOL programming, the flip-flop switching is automatically deactivated however and can also not be re-activated!

Follow vehicle-related wiring diagrams Test Measurement Remedy

Power supply from engine brake control switch

Voltage measurement at diagnostics connector box (test box) between Pin B14 (+) and Pin B1/2 (-) Target values: Foot control switch, engine brake actuated: UBat

− Test line

− Test plug-in connection

− Is bridge on ZE, position 61 plugged in?

− Replace engine brake control switch

Solenoid valve, engine brake

Voltage measurement at diagnostics connector box (test box) between Pin A18 (+) and Pin B1/2 (-) Start engine and run up to approx. 1100 rpm Target values: Foot control switch, engine brake actuated: Ubat engine brake must function

− Test line


− Replace solenoid valve, engine brake

− If no fault is found, try replacing the control unit

T 17-A2 8.40 - 63

DIAGNOSIS TEST 58

FGB/FGR switch Flash code: No data acquisition Error location (hex): No data acquisition Error display: No data acquisition Error path: FGB/FGR switch Effect of error: No switchover to FGB is possible Function: Refer to page 3.01 - 3 Possible cause of error: Line interruption, short-circuit, FGR/FGB switch faulty Condition for testing: Diagnostics connector box (test box) connected Follow vehicle-related wiring diagrams


Supply voltage

Switch on ignition Voltage measurement at diagnostics connector box (test box) between Pin B22 (+) and Pin B1/2 (-) Target values: FGB/FGR switch activated: UBat

− Test line


− Test/replace FGB/FGR switch

8.40 - 64 T 17-A2

DIAGNOSIS TEST 59

Relay, redundant shutdown MAR (safety relay) Flash code: No data acquisition Error location (hex): No data acquisition Error display: No data acquisition Error path: Relay, redundant shutdown (safety relay) Effect of error: Engine shuts down Engine does not start Function: The safety relay fulfils an important function as an independent, higher ranking

(redundant) shutdown facility of the engine. Actuation of the safety relay takes place in certain emergency situations when shutting down the engine by control to zero is no longer possible. The safety relay is actuated by the engine control unit Pin B18 and interrupts the power supply to the pump control unit (Pin 7). This leads to immediate engine shutdown.

Possible cause of error: Line interruption, short circuit, safety relay faulty, actuation by the control unit faulty

(control unit faulty) Condition for testing: Diagnostics connector box (test box) connected Follow vehicle-related wiring diagrams


Function safety relay

Start engine and run at upper idling speed (control speed PWG max) Interrupt Pin B18 Engine must shut down within approx. 10 seconds

Supply voltage Switch on ignition Voltage measurement at diagnostics connector box (test box) between Pin B18 (+) and Pin B1 (-) Specified value: UBat

− Test line


− Replace safety relay If no fault can be found:

− Replace control unit

Coil resistance, safety relay

Switch on ignition Voltage measurement at diagnostics connector box (test box) between Pin B18 (+) and Pin B1 (-)

Specified value: 180 – 250 Ω

− Test line


− Replace safety relay

man injectie electronica edc m.s 6.4

Documents

error display

cause of error

entire error memory

error search cables

display error path

corresponding error

low effect of error

number of error entries