C129B Code: Meaning, Causes, and Symptoms | OBD2 Codes

C129B – Brake Pedal Position Sensor 3 Circuit High Input

 

C129B Possible Symptoms

 

Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)

 

C129B Possible Causes

 

Faulty Brake Pedal Position Sensor,Brake Pedal Position Sensor harness is open or shorted,Brake Pedal Position Sensor circuit poor electrical connection,Faulty Electronic Brake Control Module (EBCM)

 

C129B Description

 

The Electronic Brake Control Module (EBCM) uses inputs from the electronic brake control brake pedal position sensor to determine when the brake is applied and how much force is used. The electronic brake control module monitors when the driver’s foot is on the brake and locks the offset. The offset is locked when 3 out of the 4 inputs indicate the brake pedal is applied. The 4 inputs are brake pedal travel 1, brake pedal travel 2, master cylinder pressure sensor, and the brake pedal position sensor. These inputs are used to determine the driver’s braking intent which is used to the control amount of pressure applied to the wheels.