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Home >> GMC >> 2006 >> Sierra 1500 HD, RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 1347 (Transfer Case - Mp 1625/1626-NQF) >> Diagnostic Information and Procedures >> DTC C0387 >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
  1. If either DTC C0306 or DTC C0396 is set, diagnose these DTCs first.
  2. Using a DMM, with the Ignition off, check to see if motor A control and motor B control are shorted together after disconnecting the transfer case control module and the transfer case actuator.
    • If motor A control is shorted to motor B control repair the circuits as necessary. If the circuits checked good go to next step.
  3. Inspect the actuator connector for damage or corrosion.
    • If corrosion is found then repair the damage and attempt an ATC motor learn procedure. If unable to complete motor learn go to next step.
  4. Replace the transfer case shift control module with known good unit and attempt an ATC motor learn.
    • If the ATC motor learn is successful then system is OK, if not then proceed to next step.
  5. Remove the transfer actuator and check to see if the shift detent shaft is binding.
    • If the shift lever detent shaft is binding refer to Transfer Case Disassemble . If the shift lever detent shaft is not binding replace the transfer case actuator.