U0029

DTC U0029

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 Descriptor

DTC U0029
- MOST Bus Performance

For symptom byte information, refer to Symptom Byte List Symptom Byte List.

Circuit/System Description

The Media Oriented Systems Transport (MOST) bus master device shall set DTC U0029 when the MOST bus interruptions lasts long enough to interrupt MOST communication and functions, but not long enough to break the MOST bus ring.

Conditions for Running the DTC

* The system voltage is between 9-16 V.

* The ignition is ON.

* The Radio is ON.

Conditions for Setting the DTC

A current DTC sets when MOST bus communication has been interrupted more than 10 times during the monitoring cycle period.

Action Taken When the DTC Sets

Some or all of the infotainment system may be inoperative for brief periods of time.

Conditions for Clearing the DTC

A current DTC is cleared when MOST bus communication interruptions are no longer detected and the Number of MOST Communication Breaks counter remains at 0.

Diagnostic Aids

This is an intermittent connection detection DTC. All MOST device connectors should be checked for poor connections on both MOST bus circuits.

Reference Information

Schematic Reference

* Data Communication Schematics [1][2]Electrical Diagrams

* Control Module References Control Module References

Connector End View Reference

Component Connector End Views Fuel Pump and Level Sensor Assembly

Description and Operation

Data Link Communications Description and Operation Description and Operation

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. Radio ON.

2. Verify DTC U0028 is set.

• If the DTC is set
Refer to DTC U0028 U0028.

• If the DTC is not set

3. Verify DTC U0029 is not set with symptom byte 02.

• If DTC U0029 is set with symptom byte 02
Refer to DTC U2098 U2098.

• If DTC U0029 is set with other symptom bytes except 02

4. Refer to Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections to test for an intermittent condition.

Repair Instructions

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

* GMLAN Wiring Repairs GMLAN Wiring Repairs

* Control Module References Control Module References for device replacement, programming and setup