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 of control unit connector A

See M010 ENGINE MANAGEMENT CONTROL UNIT

and the battery positive

See A001 BATTERY

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 compartment junction unit, remove relay T10 from the base (it is the second from left in the bottom 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 management 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 F21 from the base unit (it is the third from the left in the bottom row).

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 cable loom connector from connector A of the engine compartment junction unit

Turn the ignition key ON.

Measure the voltage between Pin 16 of control unit connector A

See B001 ENGINE COMPARTMENT 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

Replace the fuel pump relay

Op. 1060G88 DIESEL INJECTION SYSTEM RELAYS - R R

Disconnect the cable loom 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, renew 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 renew if necessary

Replace the fuel pump

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