Circuit/System Testing
- Ignition OFF, the fuel pump should not be operating.
- If the fuel pump operates continuously, test for a short to voltage in the fuel pump supply voltage circuit. If the circuit/connections test normal, replace the fuel pump relay.
- Ignition OFF, remove the fuel pump relay from the electrical center with the J 43244 .
- Test for less than 5 ohms of resistance between the ground circuit of the fuel pump relay coil and ground.
- If greater than 5 ohms, repair the ground circuit of the fuel pump relay coil for an open/high resistance.
- Ignition ON, verify a test lamp illuminates between the ignition 1 voltage circuit of the fuel pump relay and ground.
- If the test lamp does not illuminate, repair the ignition 1 voltage circuit of the fuel pump relay for a short to ground or an open/high resistance.
- Connect a 15A fused jumper wire between the ignition 1 voltage circuit of the fuel pump relay and the supply voltage circuit of the fuel pump. The fuel pump should operate.
- If the fuel pump does not operate, test for the following conditions:
- An open/high resistance in the motor circuit of the fuel pump
- An open/high resistance in the ground circuit of the fuel pump
- If the above circuit/connections test normal, replace the fuel pump.
- Ignition OFF, connect a test lamp between the control circuit of the fuel pump relay and ground.
- Ignition ON, command the fuel pump relay ON and OFF with a scan tool. The test lamp should turn ON and OFF with each command.
- If the test lamp remains ON all the time, test for a short to voltage on the control circuit. If the circuit/connections test normal, replace the ECM.
- If the test lamp remains OFF all the time, test for a short to ground or an open/high resistance on the control circuit. If circuit/connections test normal, replace the ECM.
- If all circuit/connections test normal, test or replace the fuel pump relay.