GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    • Perform the Diagnostic System Check - Vehicle prior to using the diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B3976-Key Not Programmed

Circuit Description

When the immobilizer (PK3+) is in the learn coded key or learn more keys mode, the immobilizer checks the current key to ensure it has been configured as a proper vehicle key.

Conditions for Running the DTC

    • Ignition is in the Accessory or Run position.
    • The immobilizer is in the learn coded key or learn more keys mode

Conditions for Setting the DTC

The immobilizer has determined the current key is not configured as a proper vehicle key.

Action Taken When the DTC Sets

The security indicator will be illuminated.

Conditions for Clearing DTC

    • A current DTC will be cleared when the immobilizer detects a properly configured vehicle key.
    • A history DTC will be cleared after 100 malfunction-free ignition cycles or when a scan tool is used to clear DTCs.

Circuit/System Verification

Important: When using this diagnostic, more than one vehicle key is required to ensure proper diagnosis. If more than one key is not available at the time of service, contact the customer and ask if any other keys can be provided for service. If unavailable, a new second key can be created. While viewing DTCs with a scan tool, attempt to start the vehicle using all of the available keys. The vehicle should start with all available keys.

If any key results in inoperative starting and DTC B3976 is set as current, replace the suspect key.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Replacing Keys
    •  Adding Keys
    •  Control Module References for BCM replacement, programming and setup