Fuel Pump Circuit Tests
- Check Fuel Pump Operation By Sound
- Ensure fuel pump operates for 2 seconds after ignition switch is turned on. If fuel pump operates as specified, see FUEL INJECTOR CIRCUIT
. If fuel pump does not operate as specified, go to next step.
- Check Fuel Pump Relay
- Turn ignition off. Disconnect fuel pump relay connector and remove fuel pump relay from bracket. Disconnect connector from fuel pump relay. Connect battery to fuel pump relay terminals No. 1 and 3. Check resistance between connector terminals No. 2 and 4 of fuel pump relay. See appropriate wiring diagram in WIRING DIAGRAMS
article. If resistance is more than 10 ohms, replace fuel pump. If resistance is less than 10 ohms, go to next step.
- Check Power Supply To Fuel Pump Relay
- Turn ignition on and check voltage supply circuit between fuel pump relay connector terminal No. 1 and 2 to ground. If at least 10 volts are present, go to next step. If at least 10 volts is not present, repair power supply circuit as necessary.
- Check Harness between ECM & Fuel Pump Relay
- Turn ignition off. Disconnect ECM harness connector and fuel pump relay harness connector. Check resistance between ECM connector terminal No. 32 and fuel pump relay connector terminal No. 3. If resistance is more than one ohm, repair open circuit in harness between ECM and fuel pump relay connector. If resistance is less than one ohm, inspect ECM connector terminal for poor contact and repair as necessary. If repair is not necessary, go to next step.
- Check Power Supply To Fuel Pump
- Connect connectors to ECM and fuel pump relay. Fold down rear seatback and turn up floor mat. Remove fuel pump access hole cover. Disconnect fuel pump connector. Turn ignition on. Check voltage between fuel pump connector terminal No. 1 and ground. If at least 10 volts are present, go to next step. If less than 10 volts is present, repair open or short circuit in harness or connectors between fuel pump relay and fuel pump as necessary.
- Check Fuel Pump Operation
- Turn ignition off. Connect battery voltage to fuel pump connector terminals No. 1 and 4. If fuel pump operates, repair or replace harness connector fuel pump ground circuit. If fuel pump does not operate, replace fuel pump.
Courtesy of SUBARU OF AMERICA, INC.