FixVault

Circuit/System Testing

IMPORTANT: Repair all U-codes before performing this diagnostic.
  1. Ignition OFF, disconnect the harness connectors at the ECM X1 and the FPCM.
  2. Ignition ON, test for 0 volts between the FPCM harness connector terminal 13 and ground.
    • If greater than the specified voltage, test the fuel control enable signal circuit for a short to voltage.
  3. Ignition OFF, test for infinite resistance between the FPCM harness connector terminal 13 and ground.
    • If less than the specified range, test the fuel control enable signal circuit for a short to ground.
  4. Ignition OFF, test for 1.0 ohm or less between the ECM harness connector X1 terminal 13 and FPCM harness connector terminal 13.
    • If greater than the specified range, test the fuel control enable signal circuit for an open/high resistance.
  5. Reconnect the harness connectors at the ECM and the FPCM. Within 2 seconds of ignition ON, with a scan tool, verify that the Fuel Pump Command parameter displays ON.
    • If the parameter does not display ON within the 2 seconds of ignition ON, replace the ECM.