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Diagnostic 2

WARNING: This page is about a different car, the 2008 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.
  1. Connect the JX200 splice pack connector.
  2. Ignition OFF, disconnect the appropriate harness connector listed below at the ECM.
    • RPO LY7 - X2
    • RPO LH2 - X3
  3. Ignition ON, attempt to communicate with the TCM. Communication should not be available.
    • If communication is established, replace the ECM.
  4. Ignition OFF, disconnect the harness connector at the electronic brake control module (EBCM).
  5. Ignition ON, attempt to communicate with the TCM. Communication should not be available.
    • If communication is established, test the following serial data circuits between the ECM and the EBCM for a short between the circuits, short to ground or a short to voltage. If the circuits test normal replace the EBCM.
      • EBCM terminal B12
      • EBCM terminal B9
      • EBCM terminal B12 and terminal B9
  6. Ignition OFF, disconnect the harness connector at the TCM.
  7. Ignition OFF, test for infinite resistance between the following serial data circuits of TCM and ground.
    • RPO LY7 - Terminal F20
    • RPO LY7 - Terminal F21
    • RPO LH2 - Terminal 13
    • RPO LH2 - Terminal 14
    • If less than the specified value, test the serial data circuit for a short to ground.
  8. Ignition ON, test for less than 1-volt between the following serial data circuits of TCM and ground.
    • RPO LY7 - Terminal F20
    • RPO LY7 - Terminal F21
    • RPO LH2 - Terminal 13
    • RPO LH2 - Terminal 14
    • If greater than the specified range, test the serial data circuit for a short to voltage.
  9. Ignition OFF, test for infinite resistance between the following serial data circuit terminals.
    • RPO LY7 - Terminal F20 and terminal F21
    • RPO LH2 - Terminal 13 and terminal 14
    • If less than the specified value, test for a short between the serial data circuits.
  10. If all circuits test normal, replace the TCM.
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