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Circuit/System Testing

  1. With the ignition OFF, disconnect the harness connector at the EBCM and ESC module one at a time. After each disconnect, clear the DTC, cycle the ignition key 3 times, then retest for the DTC. DTC U2099 should reset.
    • If the DTC does not reset, replace the last module disconnected.
  2. Ignition OFF, disconnect the harness connector X3 of the BCM.
  3. With all modules disconnected, test for infinite resistance between the high speed GMLAN serial data wake up circuit and ground.
    • If less than specified, repair the wake up circuit for a short to ground.
  4. If all circuits test normal, replace the BCM.
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