【Fault description】
    As a result of the accident in the insurance company designated car repair shop repair, the car's many features are not restored. Which wiper the gap function, wireless remote control door lock function, skylight operation is not normal, automatic air conditioning temperature can not be adjusted, but unfortunately the owner had to re-send the car to my repair shop for rehabilitation, the owner asked to restore the car as soon as everything Normal function.
    【Inspection process】
    After taking the car about two days, the wiper system, skylight, air conditioning system back to normal. Next to the wireless door locks to carefully check, first of all remote control battery measurements, the results are normal. There are two basic conditions for the normal operation of the wireless door lock: one, four door lights switch and line must be no short circuit, open circuit; Second, the key unlock the switch and the line must be no short circuit, open the situation. In accordance with these requirements were on the four door lights switch and line, the key is not locked warning switches and lines have been carefully checked and measured, the results of all normal, fault in the end out where? Refer to the maintenance manual provided by the maintenance manual, the use of any one of the wireless remote control button switch, you can measure the wireless sensor remote control receiver feedback output signal voltage or waveform, the measurement, each press a remote control button, wireless remote control receiver Of the feedback output signal PDR from 1V-6V-1V cycle changes, and then use the oscilloscope test waveform is more intuitive.
    【Fault Analysis】
    The system of the inspection have been checked, should have the conditions have been basically available, in the end which is still a problem? In order to further confirm the remote control and wireless remote control receiver, and the two parts of the car in another model with the normal use of the car, the situation is very normal, unlock and lock freely, which blame. At this point the car temporarily put it, to access the information to re-organize maintenance ideas, may be conducive to the next step in the diagnosis. About an hour later back to the car ready to repair, suddenly heard the car radio is still playing music, I thought wrong, the car keys in my hands, and play music using the sound and the radio must be screwed to the ACC switch , The original workshop two students in the car to listen to music, I quickly called the students out, remove the audio assembly to check the sound of the power supply situation, the original check should be the ACC file power supply wiring harness has become an ordinary fire, that is Said that the battery is directly powered.
    Is this fault related to this? In order to solve this question, had to re-below the dashboard of the fuse box, a variety of connectors, connectors for carpet inspection, did not find the line changes. Finally, when unplugging the ignition switch seat plug harness, occasionally found on the plug B + and ACC position has a very small short copper, it will B + and ACC were shorted, if not carefully look can not see The Will be shorted copper wire removed, the radio has no ACC power, but the rotary switch to the ACC power is normal, the radio is back to normal, readily press the remote control any button, the wireless door to return to normal. But what is the basic cause of the failure? Another analysis of the circuit diagram, the original wireless remote control computer output signal into the body ECU, and then by the body ECU to control each door lock motor work, and body ECU has a power relay from the ACC relay, when the key is not inside the ignition cylinder, You can use the wireless remote control door lock, this harness no 12V voltage, and as long as the key in the ignition lock cylinder or key in the ACC file, the harness has 12V voltage, then wireless remote control lock does not work. In general, the body ECU operation is not enough conditions caused by the failure, and precisely under normal circumstances, this wiring harness there is no measurement point, it is by the body ECU and the fuse box through the internal plug, so this fault is too special The.