2398915 - Z52 LEAN FUEL SYSTEM

The Customer reports occasional hardening during the rotation of the steering wheel (no power assistance), without the failure warning light coming on
Results of the tests
1INTAKE AND EXHAUST SYSTEM LEAKAGE CHECKAll OKProblems metOperation
Check the intake and exhaust system visually and by listening, to check that there are no leaks downstream of the MAP sensor/flow meter.

Also take into account:

  • Blow-by circuit;
  • Canister circuit, checking that the valve is not stuck open;
  • Brake servo vacuum pipes;
  • Injector O-Rings
Continue to Step 2There are leaksEliminate leaks from the system. Replace faulty parts if necessary Continue to Step 5
2PETROL PRESSURE CHECKAll OKProblems metOperation
Turn the key to MAR and check that fuel pump activates.Whilst the pump is activated, check that the fuel pressure is not too lowContinue to Step 3Low pressure: fuel filter blocked/obstructedReplace the fuel pupm Op.   1040A70  Continue to Step 5
Low pressure: supply pipe restrictions/leaksRenew or, if necessary, replace the pipes involved
Low pressure: pressure regulator defectiveReplace the fuel pupm Op.   1040A70  Continue to Step 5
Low pressure: pressure regulator incorrectly calibratedReplace the fuel pupm Op.   1040A70  Continue to Step 5
Low pressure: electrical problem in the fuel pumpLow pressure: electrical problem in the fuel pump See   E5030  PETROL ENGINE ELECTRONIC MANAGEMENT If necessary, replace the fuel pump Op.   1040A70  Continue to Step 5
Low pressure: excess pressure valve stuck openReplace the fuel pupm Op.   1040A70  Continue to Step 5
3FUEL QUALITY CHECKAll OKProblems metOperation
Check that there is no water or other substances in the tank which is contaminating the fuel.Continue to Step 4Impurities presentClean the tank Op. 1040A24and introduce new fuel.Continue to Step 5
4UPSTREAM LAMBDA SENSOR CHECKAll OKProblems metOperation
Continue as instructed in the Table See table   Z56  UPSTREAM LAMBDA SENSOR SIGNAL ERROR , starting from Step 3End of diagnosis
5ERROR CANCELLING AND CHECKINGAll OKProblems metOperation
Use a tester to cancel the errors in the control unit.Road test the vehicle and check that the error does not occur againContinue to Step 6The fault persistsContinue to Step 1
6CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Check that the fault is no longer presentEnd of diagnosis