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Home >> Cadillac >> 2012 >> Escalade EXT >> Repair and Diagnosis >> Engine Performance >> System >> Data Communications System >> Diagnostic Information and Procedures >> DTC U1814 >> Circuit/System Testing
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Circuit/System Testing

  1. With the ignition OFF, disconnect the module harness connectors listed below one at a time. After each disconnect, retest for current DTCs. DTC U1814 should remain current.
    • Engine control module (ECM) - X1
    • Transmission control module (TCM) - X1
    • Transfer case control module (TCCM) (RPO NP8) - X2
    • Serial data gateway module (SDGM) (RPO HP2) - X2
    • If the DTC becomes history, replace the module disconnected before the DTC became history.
  2. Ignition OFF, disconnect the X4 harness connector at the BCM.
  3. Test for infinite resistance between the accessory wake up serial data circuit terminal 19 and ground.
    • If less than the specified range, test the serial data circuit for a short to ground.
  4. If the circuit tests normal, replace the BCM.
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