FUEL PUMP CONTROL CIRCUIT
PCM provides ignition voltage to control fuel pump. PCM has
ability to detect an electrical malfunction on relay control circuit.
When ignition is first turned on, PCM energizes fuel pump relay which
applies power to fuel pump. Fuel pump relay will remain on as long
engine is running or cranking and PCM is receiving reference pulses.
If no reference pulses are present, PCM de-energizes fuel
pump relay within 2 seconds after ignition is turned on or engine is
stopped. With engine off/stopped, fuel pump can be turned on by using
scan tool output controls function. If electrical malfunction is
detected, DTC will set.
Engine may not start or stay running
- Disconnect fuel pump relay. Connect a test light between
fuel pump relay connector cavities for fuel pump relay control circuit
and relay ground. Install scan tool. Turn ignition on, with engine
off. Using scan tool, command fuel pump relay on and off. If test
light illuminates when fuel pump is commanded on,
- Check fuel pump relay
- Check for poor terminal connection at fuel pump relay
- Check for any shorted wires