Mike's Workshop Manuals: Service manuals for every vehicle
Home >> Pontiac >> 2008 >> G8 Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Control System & Fuel System - 3.6L - DTC P0300 To DTC P1014 >> DTC P0627, P0628, or P0629 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the fuel pump relay.
  2. 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.
  3. Connect a test lamp between the control circuit terminal 86 and ground.
  4. 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.
  5. 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.
  6. If all circuits test normal, test or replace the fuel pump relay.
scientia non olet · About Mike's Workshop Manuals