C0241

DTC C0241 or P0856

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 Descriptors
DTC C0241
- Powertrain Control Module (PCM) Indicated Requested Torque Malfunction

DTC P0856
- Traction Control Torque Request Circuit

Circuit Description

The electronic brake control module (EBCM) and the engine control module (ECM) simultaneously control the traction control system (TCS). The EBCM sends a Requested Torque message via a pulse width modulated (PWM) signal to the ECM. The duty cycle of the signal is used to determine how much engine torque the EBCM is requesting the ECM 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 ECM 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 ECM detects that requested torque signal is out of the valid range.
* The ECM 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 DTC will be current for as long as the fault is present.
* When the fault is no longer present, the DTC will be a history DTC.
* A history DTC will clear after 100 ignition cycles.

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

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

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool Torque Request Signal parameter, the reading should be 90 percent.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the EBCM.
2. Ignition ON, test for 4.7-4.8 volts between the requested torque signal circuit terminal 38 and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

3. If all circuits test normal, replace the EBCM.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

Control Module References (Programming and Relearning) for ECM and EBCM replacement, setup and programming