C1239 Code: Meaning, Causes, and Symptoms | OBD2 Codes

C1239 – Foreign Object Attached On Tip Of Left Rear Sensor


C1239 Possible Symptoms


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


C1239 Possible Causes


Faulty Left Rear Speed Sensor,Left Rear Speed Sensor rotor,Sensor installation,Brake actuator (skid control ECU)


C1239 Description


The speed sensor detects wheel speed and sends the appropriate signals to the ECU. These signals are used to control the ABS control system. The front and rear rotors have 48 serrations each. When the rotors rotate, the magnetic field emitted by the permanent magnet in the speed sensor generates AC voltage. Since the frequency of this AC voltage changes in direct proportion to the speed of the rotor, the frequency is used by the ECU to detect the speed of each wheel.