Cellular, Entertainment, and Navigation

DTC U0255-U0257

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC U0255
- Lost Communication with Info Display Module

DTC U0256
- Lost Communication with Infotainment Faceplate Control Module

DTC U0257
- Lost Communication with Info Display Module/Infotainment Faceplate Control Module

Circuit/System Description

The radio information display and controls are separate components from the radio. One or more configurations may be possible, dependent upon the available content for the vehicle. The DTC(s) that can set when a malfunction occurs can vary due to calibration differences required for the vehicle content.

Diagnosis of these communication DTCs is based upon the symptom observed in the vehicle.

Monochrome Displays

When the vehicle is equipped with a monochrome display, the radio and the display communicate with each other via CGI serial data. The radio controls communicate with the display via LIN communications, and the control messages are passed through to the radio.

When the display and controls are combined in an assembly, the communication between the two components occurs within the assembly. If the two components are separate, the communication between the display and the controls is external, via the wiring harness.

Color Displays

When the vehicle is equipped with a color display, the display and controls communicate individually with the radio. The radio communicates directly with the controls via CGI serial data. A dedicated video cable is used to communicate graphical information between the radio and the display.

For non-touch color displays, a dedicated dimming circuit is used. The radio provides an output to the display based on dimming level information the radio receives.

Touch screen color displays use touch serial data communication between the display and the radio to exchange touch data, backlighting, and dimming levels.

Diagnostic Aids

* When equipped with a monochrome display, if the display is inoperative, the main radio controls will also be inoperative.

* The functions available on the steering wheel controls (if equipped) will continue to operate if the main radio controls are inoperative.

* The DTC may be stored as a history DTC without affecting the operation of the display or controls.

Reference Information

Schematic Reference

Radio/Navigation System Schematics Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

Radio/Audio System Description and Operation (with Color Display) Radio/Audio System Description and Operation (with Color Display)Radio/Audio System Description and Operation (with Monochrome Display) Radio/Audio System Description and Operation (with Monochrome Display)

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON, A11 radio ON.

2. Verify the P17 Info Display Module turns on and information is shown on the display.

• If P17 Info Display Module does not turn on, or information is not shown in the display.
Refer to Radio Information Display Malfunction (with Monochrome Display) Radio Information Display Malfunction (with Monochrome Display)Radio Information Display Malfunction (with Color Display) Radio Information Display Malfunction (with Color Display).

• If the P17 Info Display Module turns on and information is shown on the display.

3. Verify that all radio controls operate and perform the correct function.

• If some, but not all, controls operate normally.
Replace the radio controls.

• If all controls are inoperative.
Refer to Radio Controls Malfunction (with Monochrome Display) Radio Controls Malfunction (with Monochrome Display)Radio Controls Malfunction (with Color Display) Radio Controls Malfunction (with Color Display).

• If all radio controls operate and perform the correct function.

4. All OK.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.