GM Service Manual Online
For 1990-2009 cars only

Diagnostic Instructions

    •  Perform the Diagnostic System Check - Vehicle prior to using this 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

DTC B0997 00: Auxiliary Electronic Control Unit (ECU) 2 Performance

Circuit/System Description

The navigation radio communicates with the navigation display via serial data. If the navigation radio receives an improper status response message, DTC B0997 will set.

Conditions for Running the DTC

    • The ignition is in the RUN or ACC position.
    • The system voltage is greater than 9.5 volts and less than 15.5 volts.
    • All the above conditions are present for greater than 10 seconds.

Conditions for Setting the DTC

The navigation radio receives an improper status response message back from the navigation display assembly.

Action Taken when the DTC Sets

No action is taken.

Conditions for Clearing the DTC

    • A current DTC clears when the navigation radio receives the proper response message from the radio control assembly.
    • A history DTC clears after 50 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Verify that DTC B0997 is not set.

If the DTC is set, replace the navigation display assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Radio, Video, Audio Disc Player, and Navigation Information Display Replacement