FixVault

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the fuel pump.
  2. Connect a test lamp between the control circuit terminal D and ground.
  3. Ignition ON, command the fuel pump ON and OFF using a scan tool ECM fuel pump output control. The test lamp should turn ON and OFF, as commanded.
    • If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the FPCM.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the FPCM.
  4. Ignition OFF, connect a test lamp between the control circuit terminal A and the control circuit terminal D.
  5. Ignition ON, command the fuel pump ON using a scan tool. The test lamp should illuminate.
    • If the test lamp does not illuminate, test the control circuit terminal A for a short to voltage or an open/high resistance. If the circuit tests normal, replace the FPCM.
  6. If all circuits test normal, replace the fuel tank fuel pump module.