Diagnostic Trouble Code (DTC) List

1999 GMC Forward Control 5.7 R, AutomaticSECTION Diagnostic Trouble Code (DTC) List
WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.
Diagnostic Trouble Code (DTC) List

DTC Diagnostic Procedure Module(s)
IMPORTANT: Unless otherwise directed by the Diagnostic System Check diagnose all Bxxxx Codes prior to diagnosing any Pxxxx codes.
B2960 DTC B2960  VTD
B3031 DTC B3031  VTD
B3055 DTC B3055  VTD
B3064 Content Theft Deterrent (CTD) Does Not Disarm with Key Lock  BCM
B3069 Content Theft Deterrent (CTD) Does Not Disarm with Key Lock  BCM
P1626 DTC P1626  PCM
P1629 DTC P1629  PCM
P1630 DTC P1630  PCM
P1631 DTC P1631  PCM
Pxxxx Pxxxx other PCM DTCs
Refer to Diagnostic System Check - Engine Controls in Engine Controls
PCM
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.