C1236 MERCURY, LINCOLN, FORD, MAZDA: LEFT REAR WHEEL SPEED SENSOR INPUT SIGNAL MISSING
POST UPDATED IN May, 2023
C1236 Code failures by brands
Description of DTC code C1236
Various signals indicating wheel speed are sent to the Anti-Lock Brake System Module. This data is provided by the Wheel Speed Sensors and it is from this information that the controller determines if it is necessary to activate the ABS System.
The purpose of a Wheel Speed Sensor is to detect the magnetic field of the sensor ring once it passes over the sensor face while in operation. The sensor circuit is connected to the ABS Module through two wires and a connector for each sensor. By placing the ignition switch in the RUN position, the ABS Module performs checks by sending a reference voltage to all sensors through its circuitry to verify that it is working properly
When the C1236 OBDII fault code is set, it is because the input signal corresponding to the Left Rear Wheel Speed Sensor was not detected.
Symptoms of fault code C1236
- Check Engine lamp illuminates.
- The lamp warning of ABS and Traction Control System faults is illuminated.
- Some ABS features cannot be performed.
Causes of OBD2 C1236
The reasons for the C1236 OBD2 diagnostic code being set are:
- A tire may have inconsistency in tire size.
- The Left Rear Wheel Speed Sensor may have bad wires or connectors.
- The Left Rear Wheel Speed Sensor ring may be defective.
- The Left Rear Wheel Speed Sensor may be in poor condition.
- The ABS Module may be defective.
Possible solutions of the DTC code C1236
The steps to correct the DTC C1236 OBDII code are as follows:
- As a first step consult the TSBs.
- Check if other DTCs are stored in addition to the C1236 code. If it is the case and they are related to the ABS System, diagnose them following the order shown.
- Inspect all wiring and connections of the Left Rear Wheel Speed Sensor. If, after the checks are completed, you discover damage due to burns or wear, make the corresponding repairs.
- Following the manufacturer's recommendations, diagnose the Left Rear Wheel Speed Sensor. Check that it meets the specifications and if you determine that it is damaged, consider replacing it.
