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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Pontiac G8. 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 at the DLC and ground.
    • If greater than 1.0 ohm, test the ground circuit for open/high resistance.
  2. Remove the terminating resistor.
  3. Test for 110-130 ohms between the terminals at the terminating resistor.
    • If not within the specified range, replace the terminating resistor.
  4. Connect the terminating resistor.
  5. Ignition OFF, disconnect the harness connector X3 at the BCM.
  6. Test for less than 2 ohms on the serial data circuit between terminal 6 of the DLC and harness connector X3, terminal 8 at the BCM.
    • If greater than the specified range, test the serial data circuit for open/high resistance.
  7. Verify a test lamp illuminates between each ground circuit terminal of the BCM listed below and B+.
    • X3 terminal 1
    • X3 terminal 5
    • If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  8. Ignition OFF, disconnect the harness connectors X1 and X3 at the BCM.
  9. Ignition ON, verify a test lamp illuminates between each B+ circuit terminal of the BCM listed below and ground.
    • X1 terminal 14
    • X1 terminal 21
    • X3 terminal 3
    • If the test lamp does not illuminate, test the appropriate B+ circuit for an open/high resistance or short to ground.
  10. Ignition OFF, disconnect the harness connector at the EBCM (except 6L80 transmission) or TCM (6L80 transmission).
  11. Ignition ON, test for less than 1 volt between the serial data circuit terminal 6 at the DLC and ground, and terminal 14 at the DLC and ground.
    • If greater than the specified range, test the serial data circuit for a short to voltage.
  12. Test for infinite resistance between the serial data circuit terminal 6 at the DLC and ground, and terminal 14 at the DLC and ground.
    • If less than the specified value, test the serial data circuit for a short to ground.
  13. Test for infinite resistance between the serial data circuits terminal 6 and terminal 14 at the DLC.
    • If less than the specified value, test the serial data circuits for a short between the circuits.
  14. Connect the harness connectors at the BCM and the EBCM (except 6L80 transmission) or TCM (6L80 transmission).
  15. Disconnect the harness connector X3 at the ECM.
  16. Attempt to communicate with the BCM. Communication should not be available.
    • If communication is available, replace the ECM.
  17. Ignition OFF, disconnect the harness connector X1 at the TCM (6L80 transmission) or harness connector X1 at the EBCM (except 6L80 transmission).
  18. Attempt to communicate with the BCM. Communication should not be available.
    • If communication is available, test the serial data circuits for a short between the circuits, short to voltage, or a short to ground between the TCM (6L80 transmission) or EBCM (except 6L80 transmission) and the ECM. If the circuits test normal, replace the TCM (6L80 transmission) or EBCM (except 6L80 transmission).
  19. Ignition OFF, disconnect the harness connector at the EBCM (6L80 transmission) or TCM (except 6L80 transmission).
  20. Attempt to communicate with the BCM. Communication should not be available.
  21. If communication is available, test the serial data circuits for a short between the circuits, short to voltage, or a short to ground between the EBCM ( 6L80 transmission) or TCM (except 6L80 transmission) and the TCM (6L80 transmission) or EBCM (except 6L80 transmission). If the circuits test normal, replace the EBCM (6L80 transmission) or TCM (except 6L80 transmission).
  22. Ignition OFF, connect the harness connectors at the EBCM, TCM and ECM.
  23. Ignition OFF, disconnect the harness connector at the steering angle sensor. Attempt to communicate with the EBCM. Communication should not be available.
    • If communication is available, test the serial data circuits for a short between the circuits, short to voltage, or a short to ground between the steering angle sensor and the terminator resistor. If the circuits test normal, replace the steering angle sensor.
  24. Ignition OFF, disconnect the harness connector X3 at the BCM.
  25. Ignition ON, test for less than 1 volt between the serial data circuits of BCM terminal 8 and ground, and between BCM terminal 9 and ground.
    • If greater than the specified range, test the circuit for a short to voltage.
  26. Test for infinite resistance between the serial data circuits at BCM terminal 8 and ground, and between BCM terminal 9 and ground.
    • If less than the specified value, test the circuit for a short to ground.
  27. Test for infinite resistance between the serial data circuits terminal 8 terminal 9 at the BCM.
    • If less than the specified value, test the serial data circuits for a short between them.
  28. If the circuits test normal, replace the BCM.
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