C0242

DTC C0242

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptor
DTC C0242
- ECM Indicated TCS Malfunction




Circuit/System Description

The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control. The EBCM sends a high speed GMLAN serial data message to the ECM requesting torque reduction. When certain ECM DTCs are set, the ECM will not be able to perform the torque reduction for traction control. A serial data message is sent to the EBCM indicating that traction control is not allowed.


Conditions for Running the DTC

* The ignition is ON.
* Ignition voltage is greater than 8 volts.



Conditions for Setting the DTC

The ECM diagnoses a condition preventing the engine control portion of the traction control function and sends a serial data message to the EBCM indicating that torque reduction is not allowed. The ECM will typically set other DTCs and the EBCM will set DTC C0242.


Action Taken When the DTC Sets

* The EBCM disables the traction control system (TCS) for the duration of the ignition cycle.
* The traction control off indicator turns ON.
* The driver information center (DIC) displays the TRACTION SYSTEM OFF message.
* The antilock brake system (ABS) remains functional.



Conditions for Clearing the DTC

* The condition for the DTC is no longer present.
* The electronic brake control module (EBCM) automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles.



Diagnostic Aids

This DTC is for information only. As an aid to the technician, this DTC indicates that there are no problems in the ABS/TCS.


Reference Information
Schematic Reference

Antilock Brake System Schematics ([1][2]Antilock Brakes / Traction Control Systems)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

ABS Description and Operation (Description and Operation)
Electrical Information Reference

* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Circuit Testing (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)