Circuit/System Testing
- Ignition OFF, remove the fuel pump relay from the underhood fuse block assembly.
- Ignition ON, load test for battery voltage between the ignition 1 voltage circuit of the fuel pump relay and ground.
- If less than B+, repair the ignition 1 voltage circuit of the fuel pump relay for a short to ground or an open/high resistance.
- With the ignition OFF, connect a test lamp between the control circuit and the ignition 1 voltage circuit of the fuel pump relay.
- With the ignition ON, use a scan tool to command the fuel pump relay ON. The test lamp should turn ON for about 3-5 seconds and then turn OFF.
- If the test lamp remains ON all the time, test for a short to ground on the control circuit. If circuit/connections test normal, replace the ECM.
- If the test lamp remains OFF all the time, test for a short to voltage or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
- If all circuits/connections test normal, test or replace the fuel pump relay.