P1501

PUMP RELAY





Fault Symptoms.
Engine fails to start.
Engine misfires occasionally.
Other diagnostic trouble codes, such as adaptation, misfiring, etc.

Conditions.
P1501
^ Ignition switched off.
^ Fuel pump relay turned off by the control module.
^ Battery voltage 7.5-17 V.
^ Short circuit to battery negative (B-).

P1502
^ Engine speed >80 rpm.
^ Battery voltage 7.5-17 V.
^ Fuel pump relay activated by the control module.
^ Short circuit to battery positive (B+).

P1541
^ Ignition switched off.
^ Fuel pump relay turned off by the control module.
^ Battery voltage 7.5-17 V.
^ Open circuit.





Diagnostic Help.
The pump relay can be activated with the ISAT scan tool.
- Select "ACTIVATE".
- Select "PUMP RELAY".

The command activates the pump relay at a frequency of 0.5 Hz for 30 seconds.

Make sure that the anti-theft alarm is in working order as the lead between the pump relay and the control module goes via the alarm.

Check The Wiring.
Intermittent faults may occur as a result of temporary short circuits and breaks in the wiring. Jiggle the wiring at several points and in different directions to ascertain whether the wiring harness, including any connectors, is causing the trouble. Observe the multimeter ISAT scan tool or test lamp while doing this.





Diagnostic Procedure.
1. Check the pump relay's control voltage.

- Remove the fuel pump relay.
- Connect a test lamp to pin 86 of the relay socket and a good ground.
- Turn the ignition switch to the ON position.

The test lamp should light up.

Did the test lamp light up?
YES: Continue with point 2.
NO: Check and if necessary repair or replace the lead between pin 86 of the pump relay socket and pin 87 of the main relay socket. The continue with point 3.

2. Check the control module's output to the fuel pump relay

- Connect a test lamp to battery positive (B+) and relay socket pin 85.
- Connect the ISAT Scan Tool.
- Turn the ignition switch to the ON position.
- Select "ACTIVATE".
- Select "PUMP RELAY".

The test lamp should flash at a frequency of 0.5 Hz for 30 seconds.

Test lamp flashing?
YES: Change the fuel pump relay. Then continue with point 3.
NO: Check and if necessary repair or replace the lead connected via the anti-theft alarm between pin 85 of the relay socket and pin 63 of the control module. Then continue with point 3.





3. Final check

- Clear the diagnostic trouble code.
- Implementation of driving cycle:
^ Drive the car at varying engine loads and rpm for 5 minutes.
- Evaluation of the driving cycle:
^ Check whether the diagnostic trouble code has recurred.

Has the diagnostic trouble code recurred?
YES: Continue at "Before Replacing a Control Module". Component Tests and General Diagnostics
NO: The steps taken to rectify the fault were correct.