Circuit/System Testing
- Ignition OFF, disconnect the fuel pump relay.
- Test for less than 5 ohms between the ground circuit terminal 85 and ground.
- If greater than the specified range, repair the ground circuit for an open/high resistance.
- Connect a test lamp between the control circuit terminal 86 and ground.
- Ignition ON, command the fuel pump ON and OFF with a scan tool. The test lamp should turn ON and OFF as commanded.
- If the test lamp remains OFF all the time, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
- If the test lamp remains ON all the time, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
- Test for 2-3 volts on the control circuit of the fuel pump relay.
- If the voltage is not within the specified range, replace the ECM.
- If all circuits test normal, test or replace the fuel pump relay.