Circuit/System Testing
IMPORTANT:
Repair all U-codes before performing this diagnostic.
- Ignition OFF, disconnect the harness connectors at the ECM X1 and the FPCM.
- 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.
- 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.
- 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.
- 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.