2398746 - D21 ENGINE CUTS OUT WHILST DRIVING

The engine cuts out suddenly whilst driving. Later, after starting normally, it works again
Results of the tests
0PRELIMINARY CHECKSAll OKProblems metOperation

Preliminarily check:

  • that there is fuel in the tank
  • the engine wiring is properly connected to earth
  • battery earth correctly fixed
  • correct fixing of positive battery terminal and that all leads are connected
  • no water in the fuel filter
Continue to Step 1No fuelIntroduce fuel
Fastenings slack or oxidizedRe-attach correctly
Presence of water in the fuel filterClean the tank and pipes and replace the filter element Op.   1044B20 
1CHECK WITH DIAGNOSTIC EQUIPMENTAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socketCheck that there are no errors in the control unitContinue to Step 2An error is detected in the control unitContinue 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 errors stored in the control unit memoryContinue to Step 3An error is detected in the control unitContinue following the instructions for the diagnostic equipment
3INJECTOR HIGH PRESSURE CHECKAll OKProblems metOperation
Check, as described in the test See Test   1060C  Injector high pressure fuel circuit check , that diesel leaks from the injector recirculation connections are small and about the same as one another.Continue to Step 4Consistent leak from one injectorReplace the injector Op.   1060F10 
4HIGH PRESSURE CHECKAll OKProblems metOperation
Connect the diagnostic equipment (Examiner or other instruments) to the diagnostic socketCheck as described in the test See Test   1060D  Check high pressure fuel circuit that the diesel pressure parameter is correct Continue to Step 12Pressure not correctContinue to Step 5
5CHECK ON RETURN LOW PRESSUREAll OKProblems metOperation
Check as described in the test See Test   1060A  Low return fuel pressure circuit check that the pressure in the return pipe to the tank is under 1 barContinue to Step 6Pressure above maximum limit: return pipe to tank blockedRepair the pipe; if necessary replace it
6LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Check as described in the test See Test   1060B  Low fuel pressure supply circuit check that the diesel pressure between filter and pressure pump is between 2 and 3 barContinue to Step 12Pressure below minimum limit or above maximum limitContinue to Step 7
7CHECK ON CORRECT OPERATIONAll OKProblems metOperation
Choke the return pipe from the pressure regulating valve and repeat the test See Test   1060B  Low fuel pressure supply circuit check with the pipe choked, checking that the pressure at the filter outlet is below 2 barContinue to Step 8Pressure rises to 5 bar: blocked pressure regulation valve on filter supportReplace the valve Op. 1044B16
8LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Check that the difference in pressure upstream and downstream of the filter is less than 1 barContinue to Step 9Difference in pressure greater than 1 barReplace the diesel filter cartridge Op.   1044B20 
9LOW SUPPLY PRESSUR CHECKAll OKProblems metOperation
Check that the supply pump pressure at the filter inlet is over 2.2 barContinue to Step 12Pressure below 2.2 barContinue to Step 10
10LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Measure the difference in pressure between electric pump outlet and filter inlet, checking that it is less than 0.3 barContinue to Step 11Difference in pressure greater than 0.3 barReplace the pipe
11LOW SUPPLY PRESSURE CHECKAll OKProblems metOperation
Check as described in the test See Test   1060A  Low return fuel pressure circuit check that the pump's supply voltage is 12V and that the absorbed current is between 2 and 10 amps.Continue to Step 12Voltage < 12 VCheck electric wiring See   E5050  DIESEL ENGINES ELECTRONIC MANAGEMENT
Current > 10 Amp: pump defectiveReplace the fuel pump assembly Op.   1040A70 
Current < 2 Amp.: pump blockedReplace the fuel pump assembly Op.   1040A70  and clean the fuel tank
12CORRECT OPERATION CHECKAll OKProblems metOperation
Replace the DRV high-pressure valve and check that the fault is no longer presentEnd of diagnosisFault persistsContinue to Step 13
13CORRECT OPERATION CHECKAll OKProblems metOperation
Replace the pressure pump and check that the fault is no longer presentEnd of diagnosisFault persistsContact Technical Service for further information on the problem