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Home >> Cadillac >> 2006 >> Escalade EXT >> Repair and Diagnosis >> External Pages >> Different car >> Section 1279 (Data Communication System) >> Diagnostic Information and Procedures >> DTC U2099 >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
  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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