Honda motor accord (CP2), which has a mileage of about 36 thousand km in 2012. User reflection: the car sometimes uses the remote control of the smart key system and the button of the door handle can not unlock and lock the door, and the luggage compartment can not be opened by the remote control. Inspection and analysis: after receiving the car, the maintenance personnel listen to the description of the customer to determine the failure phenomenon, and find that the fault of the vehicle is basically the same as that described by the customer. The buttons that use the remote control and the door handle can sometimes unlock and lock the door, indicating that the basic functions of the receiver and the actuator of the intelligent key system are normal. So the maintenance personnel used the Honda MVCI special tester to read the data of the vehicle, and no abnormalities were observed through observation (Fig. 1). And enter the body electrical system to check the function of the smart key system, and did not find fault codes. Through careful reading of the maintenance manual, the maintenance personnel found that the door could not be locked even if the smart key system was normal when meeting any of the following conditions. (1) ignition switch is placed in ACC (1) or ON (II) position. (2) the engine anti-theft lock key (built-in key) is in the ignition switch. (3) users use Honda smart keys outside the test area. (4) users do not use Honda smart key for operation. (5) open the door of any car. (6) Honda smart key is in Honda smart key slot. When any of the following conditions is satisfied, even if the smart key system is normal, it can not be unlocked. (1) the door has been unlocked. (2) users use Honda smart keys outside the test area. (3) users do not use Honda smart key for operation. (4) Honda smart key is in Honda smart key slot. (5) the vehicle is running. Through the test and analysis of the above data and functions, it is shown that the emitter, receiver and actuator of the vehicle intelligent key system are normal. Why can the remote control still be unable to unlock and lock the door? By consulting the maintenance manual, the Honda intelligent key system is known as the intelligent control unit, the Honda smart key, the ignition switch control unit, the door handle contact sensor, the low frequency (LF) antenna, the radio frequency (RF) unit, the Honda intelligent key system indicator, the Honda smart key slot, and the original. Tian intelligent system is composed of key switch and remote control buzzer. Among them, the radio frequency (RF) unit includes the RF signal induction and the RF signal reception to identify the Honda smart key code, and the ignition switch control unit is built inside the ignition switch, which is used to control the steering lock solenoid valve. When the built-in key is inserted into the ignition switch or the Honda smart key code is identified, the ignition switch control unit releases the steering lock solenoid valve; the Honda smart key slot is located under the driver's side dashboard, and the intelligent key slot is built inside the LF antenna. If the Honda smart key is inserted into the slot, the engine can be started when the Honda intelligent key system is closed. The Honda smart key can be pulled out of the key slot only when the ignition switch is in the LOCK (0) position. The keyless entry system of the model vehicle is integrated with the multiple integration control system. The multichannel integrated control unit (MICU) receives the LOCK (locking) and UNLOCK (unlocked) signals from the intelligent control unit or the engine anti-theft lock free key control unit (keyless receiver). The keyless entry system allows the use of emitter to lock and block vehicles. When the LOCK (locking) button is pressed, all doors are locked. When the UNLOCK (unlock) button is pressed once, only the driver's side door is unlocked. The second door is unlocked when the UNLOCK button is pressed. If the door is not completely closed or the smart key is in the ignition, the door will not be locked with the transmitter. By analyzing the common characteristics, the maintenance personnel locked the cause of the trouble in Honda smart key slot. Troubleshooting: replacement of well known Honda smart key slot after trial run, troubleshooting.