Fuel Pump Relay / Fuel Pump

FAULT DIAGNOSIS, FUEL PUMP RELAY / FUEL PUMP

Fault Symptom.
The engine fails to start Diagnostic procedure

DIAGNOSTIC PROCEDURE

1. Checking Fuel Pump Relay Operation
Connect the Scan Tool.
Ignition switch in the ON position.
Select" ACTIVATE".
Select "PUMP RELAY".
The relay is activated for 10 seconds at 1 Hz. For longer activation the command must be repeated.
Listen for the sound of the fuel pump relay and fuel pump working. Both should be heard operating at a frequency of 1 Hz.

If only the relay can be heard, continue with point 2.

If neither the relay nor the pump can be heard, continue with point 7.

2. Checking The Fuse
Check fuse 14 and if necessary replace it.

If the fuse is OK, continue with point 3.

If the fuse is not OK and blows on repeated Scan Tool activation of the fuel pump relay, continue with point 6.





3. Checking The Fuel Pump
Apply current to the fuel pump. Connect a jumper lead across fuses 14 and 22. Listen for the sound of the pump working.

If the pump works, continue with point 4.

If the pump does not work, continue with point 5.





4. Checking The Fuel Pump Relay
Remove the fuel pump relay.
Connect a jumper lead across pins 30 and 87 of the relay base.
Listen for the sound of the fuel pump working.

If the fuel pump works, change the fuel pump relay.

If the fuel pump does not work, check the lead between pin 87 and fuse 14 and also the lead between pin 30 and battery positive and take remedial action if necessary.






5. Checking The Fuel Pump
Unplug fuel pump connector H4-4. The connector is located adjacent to the fuel pump under the luggage compartment floor.
Connect the test lamp to the 4-pin male connector, pins 1 and 2.
Select "ACTIVATE".
Select "PUMP RELAY".
The test lamp should flash at a frequency of 1 Hz.

If the test lamp flashes, change the fuel pump.

If the test lamp does not flash, first check the lead between pin 2 and grounding point G5 and then the lead between pin 1 and fuse 14 and take remedial action if necessary.





6. Checking The Fuel Pump
Unplug fuel pump connector H4-4. The connector is located adjacent to the fuel pump underthe luggage compartment floor.
Change fuse 14 and repeat the Scan Tool command "PUMP RELAY".

If the fuse blows, check the wiring between fuse 14 and pin 1 of connector H4-4 and take remedial action if necessary.

If the fuse does not blow, change the fuel pump.

7. Checking The Fuel Pump Relay
Remove the fuel pump relay.
Connect the test lamp to pins 85 and 86 of the relay base.
Ignition switch in the ON position.
Select "ACTIVATE".
Select "PUMP RELAY".
The test lamp should flash at a frequency of 1Hz.

If the test lamp flashes, change the fuel pump relay.

If the test lamp does not flash, continue with point 8.





8. Checking The Fuel Pump Relay's Voltage Supply
Connect a test lamp to pin 86 of the relay base and a good grounding point.
The test lamp should light up.

If the test lamp lights up, continue with point 9.

If the test lamp does not light up, check the lead between pin 86 and battery positive and take remedial action if necessary.

9. Checking The Fuel Pump Relay's Connection To Ground
Check the lead between pin 85 of the relay base and pin 58 of the control module.

If the lead is OK, refer to Before Replacing A Control Module.

If the lead is not OK, investigate the cause and rectify the fault.