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 B2474 07: Navigation Display Head Backlighting Performance

Circuit Description

The internal backlighting of the navigation display screen located in the navigation radio.

Conditions for Running the DTC

    • Ignition ON.
    • Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

    • The navigation radio test the navigation display backlighting antenna every 1 second.
    • The radio determines there is a malfunction or overheat condition in the navigation display backlighting.

Action Taken When the DTC Sets

The navigation backlight may be too bright, dim or blank.

Conditions for Clearing the DTC

    • A current DTC goes to history when the radio does not detect the failure for more than 1 second.
    • A history DTC clears after 50 ignition cycles with no repeat of the failure.

Diagnostic Aids

Occasionally it is possible to overheat the navigation display backlighting due to excessive ambient heat inside the vehicle. In this instance it may be necessary to allow time for the display to cool.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication Connector End Views

Description and Operation

Navigation System Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Scan Tool Data List

Circuit/System Verification

  1. Ignition OFF, allow the navigation display to cool if the ambient temperature inside the vehicle is excessive and the radio is hot to the touch. Verify the navigation display is cool and the DTC has cleared and gone to history.
  2. Ignition ON, with a scan tool, clear all DTCs and operate the audio/navigation system within the Conditions for Running the DTC. Verify the DTC does not reset.
  3. If the DTC resets, replace the radio.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for radio replacement, setup, and programming