A car with a traffic accident. After repair, the left horn, the lower arm and the left front tire are replaced and the engine is started after repair. The ABS and DSC OFF and the traction control lamp are always bright. Fault diagnosis: ABS and DSC OFF and traction control lights are lit, among which ABS is best understood, and the traction control system is mainly based on the speed signal and wheel speed sensor signal to judge the running state of the driving wheel on the road. When the driving wheel is skidding or skidding on the road, the actuators automatically adjust the brake pressure of the driving wheel brake through the traction control, and reduce the wheel speed and prevent the skidding through the adjustment process of pressure growth, pressure retention and pressure reduction, and the throttle opening is properly regulated through the auxiliary valve actuator. The engine torque is adjusted, or the engine fuel injection quantity is controlled by the engine control unit, and the engine torque is reduced. In conclusion, the traction control system is definitely related to ABS, and the body stability system should include the ABS and traction control system so that it is possible to maintain the stability of the body.