2427477 - D03 ENGINE NOT RUNNING SMOOTHLY / (IRREGULAR OPERATION)

Missing at constant speed or during accelerationDuring driving, the engine misses and loses performance
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • the condition of the air filter
  • the state of the spark plugs and leads;
  • battery earth correctly fixed
Continue to Step 1Filter element dirty, damaged or incorrectly fittedReplace or refit filter element correctly
Spark plugs dirty or damagedReplace the spark plugs Op.   5510D10 
Spark plug leads damagedReplace the spark plug leads Op. 5510D14
1CHECKING WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the Examiner diagnostic equipment to the diagnostic socket.

Check:

  • that there are no faults in the engine management control unit;
  • plausibility of all the parameters
Continue to Step 2'Supply system' error detectedSee table   Z50 
'Upstream lambda sensor' error detectedSee table   Z56 
Another error dectected in the control unitContinue following the instructions for the diagnostic equipment
Inconsistent parameterContinue following the instructions for the diagnostic equipment
2ROAD TEST WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Road test the vehicle, reproducing the conditions in which the fault arises, keeping the diagnostic equipment connected.

Check:

  • that there are no faults in the engine management control unit;
  • plausibility of all the parameters
Continue to Step 3'Supply system' error detectedSee table   Z50 
'Upstream lambda sensor' error detectedSee table   Z56 
Sudden occurrence of another error in the control unit detectedContinue following the instructions for the diagnostic equipment
Inconsistent parameterContinue following the instructions for the diagnostic equipment
3CHECK ON FUEL PRESSUREAll OKProblems metOperation
Check, if necessary on the road (to reproduce the conditions in which the fault arises), the fuel supply pressure Op.   0510C10  Continue to Step 4Pressure not correct: obstructions in 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: fuel pump electrical circuit brokenRepair fuel pump electrical circuit
Pressure incorrect: fuel pump damagedReplace fuel pump assembly
4CHECK AIR CONDITIONING SYSTEMAll OKProblems metOperation
Road test the vehicle and check whether the fault is affected by whether or not the air conditioner is switched onContinue to Step 5Fault present only with the air conditioner onSee table   L10 
5CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosisFault persists: control unit faultyReplace control unit Op.   1056B82