C121D Code: Meaning, Causes, and Symptoms | OBD2 Codes

C121D – Brake Pressure Sensor Circuit


C121D Possible Symptoms


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


C121D Possible Causes


Faulty Brake Master Cylinder,Faulty Brake Booster,Faulty Anti-Lock Brake System (ABS) Module,Anti-Lock Brake System (ABS) Module harness is open or shorted,Anti-Lock Brake System (ABS) Module circuit poor electrical connection


C121D Description


The Anti-Lock Brake System (ABS) Module monitors the Brake Pressure Sensor. The ABS Module sets the OBDII code when the Brake Pressure Sensor is not to factory specifications.