• | 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 engine control module (ECM) simultaneously control the traction control system (TCS). The PCM sends a Delivered Torque message via a pulse width modulated (PWM) signal to the EBCM. The duty cycle of the signal is used to determine how much engine torque the ECM is delivering. Normal values are between 10 and 90 percent duty cycle. The EBCM supplies the pull up voltage that the ECM 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 delivered torque signal circuit.
One of the following conditions exists:
• | The ECM detects that delivered torque signal is out of the valid range. |
• | The ECM does not receive the delivered torque signal. |
When the DTC sets the TCS cannot reduce engine torque, however the brake intervention portion of the TCS system remains operational.
• | 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. |
Antilock Brake System Schematics
Control Module References for scan tool information
Ignition ON, observe the scan tool Torque Request Signal parameter, the reading should be 90 percent.
⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the EBCM. |
⇒ | 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 EBCM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for ECM and EBCM replacement, setup and programming