Test results

Check that the air intake/vacuum circuit is working properly

Check the condition of the fuel supply circuit and make sure that it is working properly.

Also check:

• wiring on engine correctly fastened to earth;

• battery correctly fastened to earth;

• positive battery terminal and all leads connected to it correctly fastened

Go to Step 1

1. Supply fastenings slack or oxidized

2. Earth fastenings slack or oxidized

1. Restore correct fastenings

 See E1010 POWER SUPPLY

2. Restore correct fastenings

 See E1010 POWER SUPPLY

Connect an Examiner to the engine control unit and check for errors

Go to Step 2

Presence of errors

Continue as instructed by the diagnostic equipment.

Check that the diesel leaks from the injector recirculation connections are small (seepage) and roughly equal to one another, carrying out the

 See Test 1060OC INJECTOR SEAL TEST

Go to Step 3

Significant leak from one injector

Replace the injector

 Op. 1060F10 INJECTORS - R.R.

Check that the high pressure diesel parameter is correct, carrying out the

 See Test 1060OD Injector high pressure fuel circuit check

Go to Step 10

Pressure not correct

Go to Step 4

Check that the pressure in the return pipe to the tank is correct, carrying out the

 See Test 1060OA LOW FUEL RETURN PRESSURE CIRCUIT CHECK

Go to Step 5

Pressure above the maximum limit: return pipe to the tank obstructed

Repair the pipe; if necessary, replace it

Check that the diesel pressure between the filter and the pressure pump is correct, carrying out the

 See Test 1060OF PRESSURE DELTA AT THE FUEL FILTER CHECK

Go to Step 6

Pressure below the minimum limit or above the maximum limit

Go to Step 7

Check that the difference in pressure upstream and downstream of the filter is less than 1 bar

Go to Step 7

Difference in pressure more than 1 bar

Replace the fuel filter cartridge

 Op. 1044B10 FUEL FILTER ASSEMBLY - R.R. OR REPLACE

Check that the supply pump pressure at the filter inlet is correct, carrying out the

 See Test 1060OB LOW FUEL SUPPLY PRESSURE CIRCUIT CHECK

Go to Step 8

Pressure not correct

Go to Step 9

Measure the difference in pressure between the electric pump outlet and the filter inlet and check that it is less than 0.5 bar

Go to Step 10

Difference in pressure higher than 0.5 bar

Replace the pipe

Check that the pump power supply voltage is correct, as described in the

Check that the current uptake is correct, carrying out the

 See Test 1040AB SUBMERGED FUEL PUMP CHECK

Go to Step 10

1. Voltage lower than 12 V

2. Current greater than 10 A: pump defective

3. Current less than 2 A: pump obstructed

1. Renew electrical wiring

 See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

2. Replace the fuel pump

 Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R

3. Replace the fuel pump

 Op. 1040A70 SUBMERGED PUMP ASSEMBLY COMPLETE WITH LEVEL GAUGE CONTROL - R + R

and clean the fuel tank

Replace the engine management control unit

 Op. 1060G80 DIESEL ELECTRONIC INJECTION CONTROL UNIT - R.R

End of diagnosis

Test results

Check the following, in order:

- engine control unit correctly fastened to earth;

- correct fastening to earth of the battery; - correct fastening of the positive battery pole and all the cables fastened to it

- correct connection of the engine control unit connector

Go to Step 1

Battery fastenings slack or oxidized

Restore correct fastenings

Control unit earth cable fastening slack

Tighten earth lead

Engine control unit connector incorrectly connected

Correctly engage engine control unit connector

Connect the diagnosis equipment (Examiner or other instruments) to the diagnosis socket and check:

- that there are no errors in the control unit;

- parameter plausibility

Go to Step 2

Error detected in the control unit.

Continue following the instructions on the diagnostic equipment

Impossible to activate a dialogue with the control unit

Go to Step 2

Carry out a road test reproducing the conditions in which the fault occurs, keeping the diagnostic equipment connected and check:

- that there are no errors in the control unit;

- parameter plausibility

Go to Step 3

Sudden onset of errors in the control unit detected

Continue following the instructions on the diagnostic equipment

Parameters off the scale.

Continue following the instructions on the diagnostic equipment

Loss of dialogue between the control unit and the diagnostic equipment.

Restore the correct connections.

Check the continuity of the supply wiring for the coils

Check that the ignition coils are working by carrying out

 See Test 5510CI CHECK ON OPERATION OF IGNITION COILS

 See Test 5510CE IGNITION CONTROL SIGNAL CHECK

Go to Step 4

Power supply wiring to coils defective

Restore correct wiring

Coils defective

Replace coils

 Op. 5510C14 IGNITION COIL/S - R.R.

- Check the continuity of the power supply wiring

 See E5030 PETROL ENGINES ELECTRONIC MANAGEMENT

Go to Step 5

Power supply wiring to injectors defective

Restore correct wiring.

Check that the engine control unit is working properly.

End of diagnosis

Engine management control unit defective.

Replace the engine management control unit

 Op. 1056B82 INJECTION/IGNITION SYSTEM E.C.U. (ONE) - R + R