Diagnostic Instructions
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
| • | 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
Connector End View Reference
Component Connector End Views
Description and Operation
ABS Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References
