Fault diagnosis technology is an important means to maintain the normal operation of the machine. Currently, excavator faults occur frequently, which not only affects the progress of the project but also brings potential safety hazards, and the service engineers need to visit the site for inspection and troubleshooting, which has high time cost and condition limitations. Based on this, a remote troubleshooting tool is developed to improve the troubleshooting efficiency. Firstly, the fault diagnostic device is connected to the excavator to realize the mutual conversion of WIFI signal and CAN signal, and the APP developed by Android system is used to send commands, based on the signal comparison method and the case inference method, the one within a certain threshold error is regarded as no fault, and the other way around is based on the source case to guide the fault case, so as to realize the remote one-button inspection. The APP has been tested by the dSPACE simulation system in the laboratory and the on-board test of SY980, with excellent diagnostic effect, and has been put into use.