Fault diagnosis method and device for PWM driving load and driving system

The embodiment of the invention discloses a fault diagnosis method and device for a PWM driving load and a driving system. The method comprises the steps of carrying out fault detection on the PWM driving load; when a fault is detected, determining the fault type of the PWM driving load, and changing the driving of the PWM driving load through driving variable control of underlying software according to the fault type; and periodically detecting the fault of the load, and recovering the normal driving of the PWM driving load if the detection result of the PWM driving load is that a fault-freefrequency is greater than a set value in a preset detection period. According to the technical scheme provided by the embodiment of the invention, the driving state of a PWM driving bottom layer is controlled through the software, a hardware circuit does not need to be modified, the problem of diagnosis jump of the PWM driving load is simply and effectively solved, stable reporting of PWM type driving load faults is reali