C1121 Code: Meaning, Causes, and Symptoms | OBD2 Codes
C1121 – Front Left Output ABS Solenoid
C1121 Possible Symptoms
Anti-Lock Brake System (ABS) Warning Light ON,Engine Light ON (or Service Engine Soon Warning Light)
C1121 Possible Causes
Faulty ABS Actuator/Electric Unit,ABS Actuator/Electric Unit harness is open or shorted,ABS Actuator/Electric Unit poor electrical connection
The control unit computes the wheel rotating speed by the signal sent from the sensor. Then it supplies a DC current to the actuator solenoid valve. It also controls ON-OFF operation of the solenoid valve relay and motor relay. If any electrical malfunction should be detected in the system, the control unit causes the warning lamp to turn on. In this condition, the ABS will be deactivated by the control unit, and the vehicle’s brake system reverts to normal operation. The ABS actuator and electric unit (control unit) contains: An electric motor and pump, Two relays, Eight solenoid valves ( each inlet and outlet for LH front, RH front, LH rear, RH rear), and ABS control unit. These components control the hydraulic circuit that increases, holds or decreases hydraulic pressure to all or individual wheels. The ABS actuator and electric unit (control unit) cannot be disassembled and must be replaced as an assembly.