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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Chevrolet HHR. However, it is still accessible from the selected car via links, so may be relevant.
  1. Test for less than 1.0 ohm between the ground circuit terminal 5 of the DLC and ground.
    • If greater than the specified range, test the ground circuit for open/high resistance.
  2. Ignition OFF, disconnect the X2 harness connector at the BCM.
  3. Test for less than 2 ohms on the serial data circuit between terminal 6 of the DLC and terminal 1 of the BCM.
    • If greater than the specified range, test the serial data circuit for open/high resistance.
  4. Ignition OFF, disconnect the X4 harness connector at the BCM.
  5. Test for less than 1 ohm between ground circuit terminal E12 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  6. Ignition OFF, disconnect the X3 harness connector at the BCM.
  7. Ignition ON, verify a test lamp illuminates between each B+ circuit terminal D12 of the BCM and ground.
    • If the test lamp does not illuminate, test the B+ circuit for an open/high resistance or short to ground.
  8. Ignition ON, test for less than 1 volt between the serial data circuit terminal 6 of the DLC and ground, and terminal 14 of the DLC and ground.
    • If greater than the specified range, test the serial data circuit for a short to voltage.
  9. Test for infinite resistance between the serial data circuit terminal 6 of the DLC and ground, and terminal 14 of the DLC and ground.
    • If less than the specified value, test the serial data circuit for a short to ground.
  10. Disconnect the X2 harness connector at the electronic power steering control module (EPS).
  11. Test for infinite resistance between the serial data circuits terminal 6 and terminal 14 of the DLC.
    • If less than the specified value, test the serial data circuits for a short between them.
  12. Connect the X2 X3 and X4 harness connectors at the BCM and the X2 harness connector at the EPS.
  13. Disconnect the appropriate harness connector at the ECM.
    • RPO L61/LE5 - X1
    • RPO LNF - X2
  14. Attempt to communicate with the vehicle control interface module (VCIM). Communication should not be available.
    • If communication is available, replace the ECM.
  15. Ignition OFF, disconnect the harness connector at the TCM.
  16. Attempt to communicate with the VCIM. Communication should not be available.
    • If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground between the TCM and the ECM. If the circuits test normal, replace the TCM.
      • RPO L61/LE5 - 43
      • RPO L61/LE5 - 44
      • RPO L61/LE5 - 43 and 44
      • RPO LNF - 33
      • RPO LNF - 53
      • RPO LNF - 33 and 53
  17. Ignition OFF, disconnect the harness connector at the EBCM.
  18. Attempt to communicate with the VCIM. Communication should not be available.
    • If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground between the EBCM and the TCM. If the circuits test normal, replace the EBCM.
      • RPO JM4 - 21
      • RPO JM4 23
      • RPO JM4 21 and 23
      • RPO JL4 14
      • RPO JL4 11
      • RPO JL4 14 and 11
  19. Ignition OFF, disconnect the X3 harness connector at the VCIM.
  20. Attempt to communicate with the EPS. Communication should not be available.
    • If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground between the VCIM and the TCM. If the circuits test normal, replace the VCIM.
      • 9
      • 8
  21. Ignition OFF, disconnect the X2 harness connector at the BCM. Attempt to communicate with the EPS. Communication should not be available.
    • If communication is available, test the following serial data circuits for a short between the circuits, short to voltage, or a short to ground between the BCM and the VCIM. If the circuits test normal, replace the BCM.
      • 2
      • 20
  22. Ignition OFF, disconnect the X2 harness connector at the EPS.
  23. Ignition ON, test for less than 1 volt between the following serial data circuits of EPS and ground.
    • 4
    • 5
    • If greater than the specified range, test the circuit for a short to voltage.
  24. Test for infinite resistance between the following serial data circuits of EPS and ground.
    • 4
    • 5
    • If less than the specified value, test the circuit for a short to ground.
  25. Test for infinite resistance between the serial data circuits terminal 4 terminal 5 of the EPS.
    • If less than the specified Value, test the serial data circuits for a short between them.
  26. If the circuits test normal, replace the EPS.
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