• | 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. |
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.
The engine is running.
The EBCM has detected an open, short to power or short to ground on the requested torque signal circuit.
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. |
When the DTC sets the TCS can not reduce engine torque, however the brake intervention portion of the TCS System remains operational.
• | 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. |
Check for poor or intermittent connections of the EBCM and the PCM. Refer to Testing for Intermittent Conditions and Poor Connections .
Antilock Brake System Schematics
Control Module References for Scan Tool Information
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.