Fault Diagnosis, Fuel Pump Relay/Fuel Pump

FAULT DIAGNOSIS, FUEL PUMP RELAY/FUEL PUMP

Symptom of fault
The engine fails to start

Diagnostic procedure
1. Connect an ISAT scan tool.

- Ignition switched ON.
- Select the "PUMP RELAY" command in the ISAT menu "ACTIVATE".

Activation of the relay takes place for 10 seconds at 1 Hz. If a longer activation time is required, the command must be repeated.

- Listen for the sound of the fuel pump relay and fuel pump working.

Both must be heard at 1 Hz.

- If only the relay can be heard, continue with step 2.
- If neither the relay nor the pump can be heard, continue with step 7.





2. Check and if necessary replace fuse 32.

- If the fuse is intact, continue with step 3.
- If the fuse blows on repeated ISAT activation of the fuel pump relay, continue with step 6.

3. Apply power to the fuel pump.

- Connect a jumper lead between fuses 4 and 32, and listen for the sound of the pump working.
- If the pump is working, continue with step 4.
- If the pump is not working, continue with step 5.





4. Disconnect the fuel pump relay.

- Connect a jumper lead between pin 30 and pin 87 on the relay base.
- If the fuel pump is now working, install a new fuel pump relay.
- If the pump is not working, check and if necessary remedy faults in the lead between pin 87 and fuse 32 and the lead between pin 30 and Batt +.





5. Unplug connector H2-9 to the fuel pump. The connector is located under the rear seat. Note that the connector with thick cables is the correct one. The other one is connected to the level sensor.

- Connect the test lamp between both pins of the 2-pole male connector.
- Select the PUMP RELAY" command with the ISAT scan tool.

The test lamp must flash at 1 Hz.

- If the test lamp flashes, replace the fuel pump and the wiring between H4-7 and H2-9, or just the wiring.
- If the test lamp does not flash, check and if necessary remedy faults firstly between pin 2 and grounding point G5 and secondly the lead between pin 1 and fuse 32.





6. Unplug the connector H2-9 to the fuel pump. The connector is located under the rear seat. Note that the connector with thick cables is the correct one. The other connector is connected to the level sensor.

- Replace fuse 32 and repeat the ISAT command "PUMP RELAY".
- If the fuse blows, check and if necessary remedy the fault in the wiring between fuse 32 and pin 1 in connector H2-9.
- If the fuse remains intact, replace the fuel pump and the wiring between H4-7 and H2-9, or just the wiring.

7. Disconnect the fuel pump relay.

- Connect the test lamp in the relay base between pins 85 and 86.
- Ignition switched ON.
- Select "PUMP RELAY" with the ISAT scan tool again.

The test lamp must flash at 1 Hz.

- If the test lamp flashes, install a new fuel pump relay.
- If the test lamp does not flash, continue with step 8.





8. Connect the test lamp between the relay base, pin 86 and safe grounding point.

- If the test lamp does not light up, check and if necessary remedy the fault in the lead between pin 86 and fuse 17.
^ Continue fault diagnosis in the +15 circuit power supply.
- If the test lamp lights up, continue with step 9.

9. Check and if necessary remedy the fault in the lead between pin 85 and pin 56 of the ECM.

- If the lead is OK, continue at "Procedure before replacing ECM".