We have encountered a lot of ABS faults, but we share less. Today, the car craftsman and your masters repair a car with ABS fault light on. By the way, let’s talk about the wheel speed sensor. When the car came, the driver said that the ABS light on the instrument was always on, and the car failed the annual examination. Enter the system with the diagnostic instrument (machinist C80) and report the “left front wheel speed sensor” fault code.
In order to verify the accuracy of the fault code, lift the two rear wheels with a jack and rotate them by hand. At the same time, observe the data flow. The voltage of the left rear wheel and the right rear wheel on the diagnostic instrument is 0.3 ~ 0.4V, and the corresponding wheel is accurate, indicating that the sensors of the left and right rear wheels are normal. Lift and rotate the left front wheel again, the left front wheel speed data is always displayed as 0, there is no change, and the left front wheel speed signal is indeed abnormal.
These are the reasons for the abnormal wheel speed:
1. The sensor is damaged or the gap is too large;
2. ECU to sensor circuit fault;
3. ECU is damaged.