A Buick GL8 business car with a mileage of about 50 thousand km in 2010. User reflection: the remote control of the car is invalid. After receiving the vehicle: the maintenance personnel refresh the control program of the vehicle body control unit through the fault diagnosis instrument, and then test the vehicle, and the fault remains unchanged. The check found that the control lock button on the car can control the 4 door locks, indicating that the lock has no problem, the problem should be sent and received on the remote control signal. Since the remote control signal of the vehicle has 2 frequencies to choose from, the remote controller is programmed with the fault diagnosis instrument, but the trouble still can not be eliminated. The vehicle body control unit is checked again, and the emphasis of the inspection is on the signal receiving unit. No obvious problem was found from the inspected object, but it was found that 1 MP3 players were inserted in the cigarette holder hole. Was it interfering with the wireless communication. Then it was pulled out and tested, and the failure disappeared. It was the original interference source that blocked the wireless communication between the remote control and the vehicle signal receiving unit. Troubleshooting: tell users not to continue using the MP3 player, and the problem is solved satisfactorily.