Turn the ignition key OFF.

Disconnect the wiring harness connector from engine control unit connector A

Connect a shunt cable with fuse between pin 28 (wiring side) of control unit connector A

See M010 ENGINE MANAGEMENT ECU

and the battery positive

and check that the fuel pump does not activate

Replace the engine management control unit

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

In the engine bay junction unit, remove relay T8 from the base (it is the first from the bottom in the right lower row).

Measure the voltage between Pin 86 of the base unit and Earth, ensuring it is greater than 11 V.

If faults are found, restore the wiring between the engine control unit and the engine compartment junction unit

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

otherwise replace the junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

If faults are found, restore the wiring between the engine compartment junction unit and earth

See E1020 EARTHS

otherwise replace the junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

Disconnect the shunt connection cable and turn the ignition ON.

Measure the voltage between Pin 30 of the base unit and Earth, ensuring it is greater than 11 V.

Move on to Step 8

Turn the ignition key OFF.

In the engine compartment junction unit

remove fuse F30 from the base unit (it is the second from the right in the second row from the bottom).

Turn the ignition key ON.

Measure the voltage between the fuse input contact and earth, checking it is less than 11 V

Replace the junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

Turn the ignition key OFF.

Disconnect the wiring harness connector from engine control unit connector A

Turn the ignition key ON.

Measure the voltage between pin 16 (wiring side) of control unit connector A

See B001 JUNCTION UNIT

and Earth, checking it is less than 11 V

Replace the junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

Turn the ignition key OFF.

Restore the wiring between the under-dashboard junction unit and the engine compartment junction unit

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

The test can be considered over

Disconnect the wiring harness connector from the fuel pump

Measure the voltage between pump Pin 4

See N040 FUEL PUMP AND LEVEL GAUGE

and Earth, checking it is greater than 11 V

If faults are found, restore the wiring between the engine compartment junction unit and the fuel pump

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

otherwise replace the junction unit

Op. 5505A13 ADDITIONAL JUNCTION UNIT IN ENGINE COMPARTMENT - R.R.

Check the wiring between the fuel pump and earth

See E5050 DIESEL ENGINES ELECTRONIC MANAGEMENT

and restore if necessary

Replace the fuel pump

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