A journey mileage of about 20 thousand km, equipped with 2. 0L engine and manual transmission of Dongfeng Citroen Sega car. User response: the ESP system failure indicator lights on the vehicle combination meter are glinting. After receiving the car, the ESP control system of the vehicle is malfunction and read with the PROIXA3 diagnostic instrument, and the following fault information is obtained: the right front wheel without speed signal fault (P, permanent fault). Next to the other control systems of the vehicle, the corresponding fault reading operation is also carried out, and the following fault information is obtained in the automatic transmission control system: ABS (ESP) (CAN) speed fault (P, permanent fault); in the engine control system, the fault information is obtained: the communication fault with the automatic transmission (P Permanent failure). The vehicle carries on the road test operation, then uses the diagnostic instrument to carry on the parameter measurement operation to the ESP system, results the wheel speed information of the right front wheel is 0km/h, and the wheel speed signal of the other 3 wheel speed sensors is normal. A new right front wheel speed sensor assembly is replaced by the right front wheel speed sensor and a new right front wheel speed sensor assembly is replaced. Then the road test operation is carried out and the fault code deletion operation is carried out with the diagnostic instrument. The fault phenomenon still exists. The possibility of failure of the right front wheel speed sensor is eliminated. A new right forward universal joint assembly is interchanged with the right front universal joint assembly of the fault vehicle (doubtful that there is a bad job in the ring speed feedback signal on the right front universal joint assembly, causing a normal signal), and the ESP system fault indicator on the combined instrument is still flashing, indicating that the fault has nothing to do with the right front universal joint assembly.