The slip control ECU measures the speed at which each wheel is spinning by taking into account the signals sent by the Speed Sensor. These signals are used to determine if the operation of the 4 wheels is right. Therefore, all-wheel signals must be equal.
The OBDII fault code C1237 is set at the moment the Skid Control ECU finds some differences between the Four-Wheel Speed Sensor output or irregular pulse signals related to three sensors onwards.
Reasons for storing the C1237 OBD2 diagnostic code:
One of the tires may be deformed.
The Speed Sensor rotor may be damaged.
The Speed Sensor may be defective.
Slip control ECU (brake actuator assembly) may be faulty.
Possible solutions of the DTC code C1237
To solve OBDII DTC C1237, try this:
First, consult the Service Bulletins.
Check with a scan tool to see if any additional DTCs are stored, in addition to C1237. It might indicate problems with the ABS or a specific Speed Sensor. Diagnose the codes in the order displayed by the scan tool.
Check your car's tires for deformations or irregularities. If you detect problems with one of the tires, make the appropriate adjustments.
Verify that the speed sensor is not faulty, taking into account the manufacturer's recommendations. If after performing the respective tests you determine that the sensor is damaged, make the necessary corrections.