Safety Warning

DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.

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HOMESERVICE MANUALSGMC1999FORWARD CONTROL 5.7 R, AUTOMATICREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 807 (THEFT DETERRENT SYSTEM)DIAGNOSTIC INFORMATION AND PROCEDURESDIAGNOSTIC TROUBLE CODE (DTC) LIST

1999 GMC Forward Control 5.7 R, Automatic

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 2003 Buick Regal and 2003 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

DTC	Module
NOTE: Diagnose all BXXXX codes prior to diagnosing any PXXXX codes unless otherwise directed by the Diagnostic System Check.
DTC B2957	BCM
DTC B2958	BCM
DTC B2960	BCM
DTC B3031	BCM
DTC B3094	BCM
DTC P1626	PCM
DTC P1629	PCM
DTC P1630	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.