Symptom: a Lexus car, vehicle remote control function failure, the driver's side of the main electric glass lift switch can not control the other three doors of the glass lift; with the key to open the door, the vehicle alarm, the engine can not start; Memory function and steering wheel automatic telescopic function failure; with the key lock car, the vehicle can not lock; left front door door lights do not shine.
    Troubleshooting: When the vehicle set up anti-theft, if the vehicle's doors, luggage compartment and engine compartment cover is opened, the vehicle will alarm, and start the engine anti-theft system to prevent the vehicle was forced to start. As the car can not be achieved with the key lock lock function, we decided to check the vehicle left front door control switch and door computer.
    First remove the left front door of the guard, with a multimeter to check the left front door door key switch. It is confirmed that the switch can be turned on at LOCK and UNLOCK, and the measured resistance value is within the normal range. Then we checked the left front door computer power supply lines, and focus on checking the power supply of the ground line is open or virtual connection phenomenon. Check the relevant line standard values ​​according to the service manual. Car maintenance and maintenance network
    After inspection, D615-GROUND voltage is not normal, the voltage is about 9V. Measured from the fuse to the door control computer wire resistance, measured value of about 800Ω. Under normal circumstances, the resistance of this wire should be less than 1Ω. Analyze the circuit diagram again and find that there is a connector (IF1) in the middle of the wire that is connected to the fuse. So that the connector to find the inspection and found that the metal terminal has been oxidized. After making the necessary cleaning, we replace all the oxidized metal terminals. After the system will be restored and found that the key can control the door lock to open and close, but still can not use the remote control to unlock and lock, while the front door door lights do not light. In the easy repair from the easy to the principle, we first check the door of the light bulb is damaged, after confirming the normal light bulb, but the lamp holder metal terminal exposed to the outside. Check the voltage between the red lead and the GROUND of the power supply and measure it to 0V (standard value 12 to 14V). After analyzing the circuit diagram, I found that the line and just found that the connector is the same oxidation. And then disconnect the connector again to measure the connector to the lamp line is turned on, the measured resistance is less than 1Ω. And then from the other end of the connector to the fuse (DOME-FR) is between the conduction, the result is not conductive. So I checked the line from the connector (IF1) to the fuse (DOME-FR) and found that one had been disconnected and found that the fuse (DOME-FR) had been blown. So the wire wrapped in the fuse on the fuse, open the wire to repair, and once again the line recovery, the results of the door lighting is still not bright. And then check the other end of the lamp to the door control computer wire connection, the results line normal.
    And later decided to check the computer, after opening the computer's shell, smell the burning of the circuit board burning paste. Careful inspection found that the circuit board connector below the scorched traces, so replace the door control computer. After the replacement of the computer, the car's various functions back to normal.
   Failure analysis: After the accident of the car carried out a careful analysis, as the door lights and remote control anti-theft system common use of a fuse (DOME-FR), when the door lights of the two short-circuit fuse fuse fuse, The mechanic did not install the same fuse as required, so that the wires from the fuse to the IF1 were blown off (it was estimated that there had been only a small number of wires connected before that, and the power supply to the lamp could be reluctantly applied. Large, it will be worn by the root of the wire burning section, while the door control computer internal circuit board because the current is too large and burned). So that the remote control of the receiving system power supply has lost power supply, if the remote control set anti-theft if the above situation, the vehicle's remote control will fail, can not lift the anti-theft. When the user can not use the remote control to open the door lock, can only use the key to open the door, but because the door power supply line oxidation, coupled with the door control computer burned inside, the door lock can not open the signal through the door to control the computer to the body Control the computer (BODYECU), so that the vehicle to identify the abnormal opening signal, so anti-theft function is turned on.