Fuel Pump Circuit Tests
- Check Fuel Pump Operation
- 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 Ground Circuit
- Turn ignition off. Disconnect fuel pump 6-pin connector. Ensure there is less than 10 ohms resistance between connector terminal No. 3 and ground. See appropriate wiring diagram in the WIRING DIAGRAMS
article. If resistance is less than 10 ohms, go to next step. If resistance is more than 10 ohms, repair harness or connectors as necessary.
- Check Fuel Pump Power Supply
- Turn ignition on. Ensure there is at least 10 volts between fuel pump 6-pin connector terminal No. 1 and ground. If at least 10 volts are not present, go to next step. If at least 10 volts are present, replace fuel pump.
- Check Harness Resistance Between Fuel Pump & Fuel Pump Relay
- Turn ignition off. Ensure there is less than 10 ohms resistance between fuel pump connector terminal No. 1 and fuel pump relay 4-pin connector terminal No. 4. If resistance is less than 10 ohms, go to next step. If resistance is more than 10 ohms, repair harness or connectors as necessary.
- Check Fuel Pump Relay
- Disconnect fuel pump relay 4-pin connector and main relay 6-pin connector. Remove fuel pump relay and main relay with bracket. Connect battery voltage and ground to fuel pump relay terminals No. 1 and 3. Ensure there is less than 10 ohms resistance between terminals No. 2 and 4. If resistance is less than 10 ohms, go to next step. If resistance is greater than 10 ohms, replace fuel pump relay. See Fig 1
.
- Check Harness Resistance Between ECM & Fuel Pump Relay
- Disconnect ECM connectors. Ensure there is less than 10 ohms resistance between ECM 26-pin connector terminal No. 8 and fuel pump relay connector terminal No. 3. If more than 10 ohms is present, repair harness or connectors as necessary. If less than 10 ohms is present, inspect ECM connector terminal. If ECM connector is okay, replace ECM.
Courtesy of SUBARU OF AMERICA, INC.