For 1990-2009 cars

### 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

• | Radio ON.

• | Battery voltage must be between 9-16 volts.

### Conditions for Setting the DTC

• | The navigation radio tests the navigation display backlighting every 1 second.

• | The radio determines there is a malfunction or overheat condition in the navigation display backlighting.

### Action Taken When the DTC Sets

Navigation backlighting may be too bright, dim or blank.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 50 consecutive malfunction-free ignition cycles have occurred.

### 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

Component 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

Control Module References for scan tool information

### 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.

⇒ | 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