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Home >> Chevrolet >> 2008 >> HHR SS, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls And Fuel - 2.0L - DTC P0243 To DTC P0700 >> DTC P0627, P0628, or P0629 >> Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the fuel pump relay.
  2. Ignition ON, verify that a test lamp illuminates between the ground circuit terminal and B+.
    • If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance.
  3. Verify that a test lamp does not illuminate between the ground circuit terminal and the control circuit terminal.
    • If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Remove the test lamp.
  5. Command the fuel pump relay ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is OK.
    • If not the specified value, test the fuel pump relay control circuit for a short to ground. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the fuel pump relay control circuit terminal and the ground circuit terminal. Command the fuel pump ON with a scan tool. Verify the scan tool fuel pump relay Ckt. Short Grnd Test Status parameter is Fault.
    • If not the specified value, test the fuel pump relay control circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
  7. Connect a 15A fused jumper wire between the positive voltage terminal at the battery and the fuel pump voltage supply circuit terminal and verify fuel pump activation.
    • If the fuel pump does not activate, test the fuel pump voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the fuel pump.
  8. Ignition ON, connect a 15A fused jumper wire between the relay switch voltage supply circuit terminal and the fuel pump voltage supply circuit terminal and verify fuel pump activation.
    • If the fuel pump does not activate, test the relay switch voltage supply circuit for a short to ground or an open/high resistance. If the circuit tests normal and it's fuse is open, test or replace the relay.
  9. Ignition ON, verify that a test lamp illuminates between the relay coil ground circuit terminal and B+.
    • If the test lamp does not illuminate, test the relay coil ground circuit for an open/high resistance.
  10. If all circuits and the ECM test normal, test or replace the fuel pump relay.
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