2007 TOYOTA Camry cars with a mileage of about 127 thousand km. The car combination instrument work is not normal, the multi-functional display will appear the traditional characters, and the tachometer does not turn, the last shop repaired, broken battery will be good, this time again, and this phenomenon sometimes is not. After the engine started about 5min, there was no failure, flameout and restart, failure appeared, multi-function display display in the traditional text, and the "rain wiper water shortage" hint information, the tachometer did not work and no stop indicator light, driving mileage showed "0". The steering indicator and the backlight are all normal. Fault diagnosis: according to the failure phenomenon, the possible reasons are as follows: (1) external signal interference; (2) CAN line communication and internal failure of combinatorial instruments; 3 other human factors. There are no modifications to the vehicle, such as the helium lamp, the high power sound and so on, and this phenomenon appears in different places, so the possibility of external signal interference can be eliminated. Connect IT2 to read DTC, find it is impossible to enter the composite instrument system, doubt CAN line communication fault, using multimeter resistance to measure DLC3 diagnosis interface No. 6 and No. 14 (CAN H and CANL terminal) terminal resistance is 62 omega (normal 54~69 omega), measure the two terminal (+B end) resistance of the 16 terminal (+B terminal). The resistance is 1.8K ohm (standard: the resistance of the +B terminal is > 6K 6K, the earth resistance is > 200 ohms), and the CAN line is not abnormal. When the ignition switch is turned off and re opened, there is no fault. Connecting to IT2, no fault code is found in the integrated instrument system. Carry out motion test, all pointer and indicator light can correctly indicate. Here we can only simulate the fault recurrence, remove the combined instrument, shake the instrument connecting line with your hands, no abnormalities. If the plug is disconnected, there is no rusting trace on the pins and slots. Heating the instrument back with a hot air gun, the malfunction appears, and it will return to normal after its cooling. After several times, the fault is determined inside the instrument cluster. Disassemble the assembly instrument, check the appearance of each component on the circuit board, do not burn the rust trace, control the circuit diagram, the multi-function display screen and the microchip chip, and find the solder to connect the two chip feet together when checking the chip. In order to confirm the cause of the failure, we disassembled the combined instrument of the same type of vehicle, and all the chip legs were separately separated. Clean up the solder slag and load the car, troubleshooting. It was found that the mileage mileage of the car has been adjusted, and the tin slag may fall on the pin in the process of welding chip, which causes the phenomenon of virtual connection. According to the principle of heat expansion and contraction, the failure phenomenon occurs intermittently. This is a fault caused by a human factor.