C121A Code: Meaning, Causes, and Symptoms | OBD2 Codes
C121A – ABS Regenerative Axle Pressure Performance
C121A Possible Symptoms
Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)
C121A Possible Causes
Faulty Brake Pressure Modulator,Brake Pressure Modulator harness is open or shorted,Brake Pressure Modulator circuit poor electrical connection
The Electronic Brake Control Module (EBCM) uses input from the regenerative axle pressure sensor for more accurate control during a brake and vehicle stability enhancement system event. The regenerative axle pressure sensor is internal to the brake pressure modulator.