The powertrain control module (PCM) provides ignition positive voltage to the coil side of the fuel pump relay. When the ignition switch is first turned ON, the PCM energizes the fuel pump relay, which applies power to the fuel pump. The PCM enables the fuel pump relay as long as the engine is cranking or running, and crankshaft reference pulses are received. If no crankshaft reference pulses are received, the PCM de-energizes the fuel pump relay after 2 seconds. The PCM monitors the voltage on the fuel pump relay control circuit.
- Engine Light ON (or Service Engine Soon Warning Light)
- Open Inertia Switch
- Blown Fuel Pump fuse
- Open Fuel Pump Monitor Circuit
- Open Fuel Pump Control Circuit
- Faulty Fuel Pump Relay
- Damaged PCM.
For some FORD models:
1. Disconnect the inertia switch harness connector.
2. Turn key to ON position (Engine OFF)
3. Measure voltage of circuit between inertia switch harness connector and ground.
4. If battery voltage is found, replaced Inertia Switch.
5. Clear codes.
If this doesn't help, please let us know so we can do more to help you fix your vehicle.
Thursday, February 3rd, 2011 AT 11:55 PM