Fuel Pump Circuit Tests
- Check Fuel Pump Operation In D-Check Mode
- Connect test mode connector and turn ignition on. Ensure fuel pump operates for 2 seconds after turning ignition on. If fuel pump operates for 2 seconds, check fuel injector circuit. See FUEL INJECTOR CIRCUIT TESTS
. If fuel pump does not operate, go to next step.
- Check Fuel Pump Relay
- Disconnect fuel pump relay connector and remove fuel pump relay from bracket. Ensure there is 70 ohms of resistance between fuel pump relay terminals No. 1 and 3. See Fig 1
. Replace fuel pump relay if resistance is not as specified. If resistance is okay, connect positive battery lead to terminal No. 1 and negative lead to terminal No. 3. See appropriate wiring diagram in WIRING DIAGRAMS
article. If fuel pump relay does not click, replace it. If fuel pump relay clicks, verify zero ohms resistance between terminals No. 2 and 4. If resistance is as specified, go to next step. If resistance is not as specified, replace fuel pump relay.
- Check Voltage Between Fuel Pump Relay & Ground
- Turn ignition off. Remove fuel pump relay without disconnecting connector. Ensure there is at least 10 volts between fuel pump relay connector terminal No. 1 and ground. If at least 10 volts are present, go to next step. If at least 10 volts are not present, repair harness or connector.
- Check Voltage Between ECM & Ground
- Turn ignition on. Check voltage between ECM 26-pin connector terminal No. 23 and ground. Ensure there is at least 10 volts when ignition is on and zero volts while cranking engine. If voltage reading is as specified, go to next step. If voltage reading is not as specified, repair faulty connector or ground circuit. If connector and ground are okay, replace ECM.
- Check Fuel Pump Terminal Voltage
- Remove fuel pump access cover located in trunk area and remove fuel pump connector. Ensure there is at least 10 volts between 5-pin fuel pump connector terminal No. 1 and ground. If at least 10 volts are present, go to next step. If at least 10 volts are not present, repair harness or connectors between fuel pump and fuel pump relay as necessary.
- Check Fuel Pump Operation
- Disconnect fuel pump connector. Connect positive battery lead to terminal No. 1 and negative lead to terminal No. 3. If fuel pump operates, repair fuel pump grounding circuit. If fuel pump does not operate, replace fuel pump.
Courtesy of SUBARU OF AMERICA, INC.