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 Descriptors
DTC C0241: Powertrain Control Module (PCM) Indicated Requested Torque MalfunctionDTC P0856: Traction Control Torque Request Circuit
Circuit Description
The electronic brake control module (EBCM) and the powertrain control module (PCM) simultaneously control the Traction Control System (TCS). The EBCM sends a Requested Torque message via a pulse width modulated (PWM) signal to the PCM. The duty cycle of the signal is used to determine how much engine torque the EBCM is requesting the PCM to deliver. Normal values are between 10 and 90 percent duty cycle. The signal should be at 90 percent when traction control is not active and at lower values during traction control activations. The PCM supplies the pull up voltage that the EBCM switches to ground to create the signal.
Conditions for Running the DTC
The engine is running.
Conditions for Setting the DTC
C0241
The EBCM has detected an open, short to power or short to ground on the requested torque signal circuit.
P0856
One of the following conditions exists:
| • | The PCM detects that requested torque signal is out of the valid range. |
| • | The PCM does not receive the requested torque signal. |
Action Taken When the DTC Sets
When the DTC sets the TCS can not reduce engine torque, however the brake intervention portion of the TCS System remains operational.
Conditions for Clearing the DTC
| • | The condition for the DTC is no longer present and you used the scan tool Clear DTC function. |
| • | The EBCM automatically clears the history DTC when a current DTC is not detected in 100 consecutive drive cycles. |
| • | The PCM automatically clears the history DTC when a current DTC is not detected in 40 consecutive warm-up cycles. |
Diagnostic Aids
Check for poor or intermittent connections of the EBCM and the PCM. Refer to Testing for Intermittent Conditions and Poor Connections.
Reference Information
Schematic Reference
Antilock Brake System Schematics
Connector End View Reference
Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for Scan Tool Information
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
