125000495 - D03 ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

During driving, the engine misses and loses performance
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Check, in order:

  • The condition of the air intake circuit;
  • That there are no faults in the air filter
  • The seal of the diesel pipes
  • That there is no water, petrol, paraffin or dirt in the fuel tank and filter
  • That the battery earth is correctly fixed
  • That there no obstructions in the exhaust system
Continue to Step 1Fault in air intake circuitRepair the air intake circuit
Air filter blockedReplace the filter element Op.    Op. 1048A14 AIR CLEANER FILTERING ELEMENT - REPLACE.
Leak from diesel pipesEliminate the leaks
Presence of water, petrol, parffin or dirt detected.Clean the tank and pipes and replace the filter element Op.    Op. 1044B20 FUEL FILTER FILTERING ELEMENT - REPLACE
Loose battery earth terminalRestore the correct fixing of the earth cable
Obstruction in the exhaust systemReplace the damaged system component
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket

Check:

  • For errors in the control unit;
  • The plausibiilty of the parameters
Continue to Step 2An error is detected in the control unitContinue following the instructions for the diagnostic equipment
unreliable parametersContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Road test the vehicle, reproducting the conditions in which the fault arises, keeping the diagnostic socket connected

Check:

  • For errors in the control unit;
  • The plausibiilty of the parameters
Continue to Step 3An error is detected in the control unitContinue following the instructions for the diagnostic equipment
unreliable parametersContinue following the instructions for the diagnostic equipment
Lack of dialogue with the control unitRestore the connection between the engine management control unit and the diagnostic connector.
3Continue as instructed by the testerAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit faultyReplace control unit Op.    Op. 1060G80 DS ELECTRIC INJECTION CONTROL UNIT - R R
During driving, the engine misses and loses performance
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • That the battery is properly connected to earth See    See E1010 SUPPLY
  • Condition of air intake circuit
  • The condition of the spark plugs
  • Quality of the fuel
  • Check engine wiring earths
Continue to Step 1Earth fastening not correctRestore correct fixing
Air intake circuit faultRestore the correct operation of the intake circuit
Spark plugs not the type recommended by the manufacturerReplace the spark plugs Op.    Op. 5510D10 SPARK PLUGS - R+R
Impurities in the fuelClean the fuel tank
Earths faultyRestore correct fixing
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socket.

check

  • That there are no faults in the engine management control unit
  • The plausibiilty of the parameters
Continue to Step 2Error detectedContinue following the instructions for the diagnostic equipment
Inconsistent parameterAnaylze the factors that have caused this inconsistency
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Road test the vehicle, reproducing the conditions under which the fault arises, keeping the diagnostic equipment connected

Check:

  • That there are no faults in the engine management control unit
  • The plausibiilty of the parameters, in particular:
  • Rail pressure - rail pressure setting
  • Injection times
  • Rpm (graphic acquisition of the signal is best)
  • Engine temperature
Continue to Step 3Error detectedContinue following the instructions for the diagnostic equipment
Inconsistent parameterAnaylze the factors that have caused this inconsistency
3LOW PRESSURE CIRCUIT CHECKAll OKProblems metOperation
Continue to Step 4Incorrect pressure: obstructions in the fuel delivery pipeRemove the obstructions in the fuel pipe, and if necessary replace it
Pressure not correct: tank insufficiently ventilatedRestsore the tank ventilation
Pressure not correct: petrol pump damaged or not correctly suppliedReplace fuel pump assembly Op.    Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GUAGE CONTROL - R + R
4RAIL PRESSURE SENSOR CHECKAll OKProblems metOperation
Check the operation of the rail sensorContinue to Step 5Pressure sensor faultyReplace sensor Op. 1056F54
5PRESSURE REGULATOR CHECKAll OKProblems metOperation
Check that the voltage regulator is workingContinue to Step 6Pressure regulator faultyReplace the pressure regulator Op. 1056F52
6HIGH PRESSURE PUMP CHECKAll OKProblems metOperation
Check the operation of the high pressure pumpContinue to Step 7High pressure pump faultyReplace high pressure pump Op. 1056F72
7CHECK ON INJECTORSAll OKProblems metOperation
Check the continuity/insulation of the injector wiring; in particular, make sure that the injector operating signal is present See    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENTContinue to Step 8No signal, wiring brokenRenew the wiring See    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
No signal, wiring not brokenReplace engine management control unit Op. 1056F82
8IGNITION OPERATION CHECKAll OKProblems metOperation
Check the continuity/insulation of the supply circuit and the coil operation; in particular, make sure that the coil operating signal is present See    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENTContinue to Step 9No supply/earthRenew the wiring See    See E5030 PETROL ENGINE ELECTRONIC MANAGEMENT
No operating signalCheck the wiring between the coils and the ECU and, if necessary, replace the control unit Op. 1056F82
9PHASE TRANSFORMER CHECK IN ACTIVE DIAGNOSISAll OKProblems metOperation
Check the operation of the phase transformer in active diagnosisContinue to Step 10Not workingUsing a voltmeter (graphic is best) check the transformer operating signal and, if necessary, replace the transformer Op.    Op. 1036C40 TIMING VARIATOR ON INLET CAMSHAFT IN CYLINDER HEAD R + R WITH SHAFT REMOVED
10MODULAR MANIFOLD CHECK IN ACTIVE DIAGNOSISAll OKProblems metOperation
Check the operation of the modular manifold in active diagnosisContinue to Step 11Not workingUsing a voltmeter (graphic is best) check the modular manifold operating signal and, if necessary, replace the modular manifold solenoid valve Op. 1072D44
11CHECK ON TIMINGAll OKProblems metOperation
Check that the timing is correct Op.    Op. 0510A20 TIMING GEAR WITH BELT DRIVE - CHECK - CARRY OUT OPERATION WITH CAM COVER(S) REMOVED AND TAPPETS ADJUSTEDContinue to Step 12Timing not correctEnsure that the timing is correct Op.    Op. 1032B10 TOOTHED TIMING BELT - R + R FOR TIMING ADJUSTMENT OR REPLACEMENT
12Continue as instructed by the testerAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosis.