A MITSUBISHI winged car with a mileage of about 4000km. Users reflect: after the car is parked for about 1 hours each time, it needs to start the engine many times to start, sometimes it can not start, but after a period of time, it can start again. Because of intermittent faults, many failures occurred during the inspection of our factory. When the fault occurred, it was found that the starting system of the car was not working, so the starting system was checked, and the starting motor had no working voltage when the ignition key was started, but the starting motor could operate normally, but the engine could not start. At this time check MPI system found no fire, no oil, I think that the fault is not the startup system can not work normally, and not MPI system failure caused, but because the fault when the car entered the anti-theft mode, this time the start is not "legal". The car is equipped with WCM system, I think the problem is in the system, focusing on checking the WCM system. With MUT-3 into the ETACS system, check the fault code U0168, meaning KOS/WCM CAN pause (timeout). After analysis, if the signal or error key from WCM can not be accepted, the combinatorial instrument may set the fault code. When the data flow is checked, when the KEY-ST block is reserved, the 287 starting switch of the data stream is opened, indicating that the ETACS-ECU can receive the starting signal from the ignition switch, but the starting relay is not absorbed, the emphasis is on the anti-theft mode has been enabled, so the ignition key is reproduced. The registration success rate is very low (it needs to be repeated again and again. Registration), but the failure remains after success. At this time, the customer provided an important information, that is, the car had modified the folding key, and the key in the key fell to the ground when it was disassembled and installed. I suspect that the ignition key has a failure. So take a new ignition key to re - register the key, the engine can normally start, a week after the phone call back, the owner reflects the failure of no reproduction, everything is normal. In this case, it is determined that the fault is successfully eliminated. Maintenance summary: the car is newly bought because the ignition key is converted into a folding type. The technician accidentally drops the transponder in the key to the ground, causing the WCM to receive the ID code of the ignition key intermittently, so the WCM can not control the engine ECU, and the vehicle intermittently can not start.