A 2004 annual production of Shanghai Volkswagen four door luxury version of the Gol sedan, because the control of the door lock trouble station maintenance. According to the car owners commissioned by the maintenance of the contents of the failure of the following verification: the car keys into the driver's side door lock keyhole, respectively, open the door and lock the door operation, the other three doors do not have any doors and lock the door Action and sound. And then press the car keys on the door with the remote control, open the door / lock the door (with a button) operation, you can see the remote control on the work light flashing, but the four locks are still no response. Similarly, press the remote control luggage compartment lock button, luggage compartment door lock does not have any action, it seems that the car's remote control door lock and the central control system there is a certain fault.
    In order to check and troubleshoot, the service personnel read the circuit diagrams associated with them and operate and compare them in the car, clarifying the control principle of the car's control of the door lock and the remote control door lock. The key control and remote control of the door lock depends entirely on the car's anti-theft alarm system control unit J85 (hereinafter referred to as "J85"), when the car key into the driver's door lock door rotation, unlock / lock the door Operation is connected with the switch F121, and it is converted into the operation signal of the door opening / lock door. J85, J85 receives the signal and immediately drives the door lock motor in each door to unlock and lock action. If the remote control is used to complete the door lock / door opening operation, J85 will enter the burglar alarm state / anti-theft release state accordingly. The burglar alarm horn H8 and 4 turn signals L1 ~ L4 will be expressed in 2 different sounds and different shiny Its entry into the corresponding state. When the J85 enters the burglar alarm state, the J85 senses the state of the engine nacelle, the four doors and the luggage compartment cover through the closed state of the gated contact switches F1 to F6, respectively. At the same time, the J85 monitors the ultrasonic sensor G209 mounted on the dome light The movement of the car. If the door and the nacelle cover and other thieves open or broken window into the J85 will drive anti-theft alarm horn H8 and turn signal lights L1 ~ L4 alarm.
    According to the previous fault verification check and data analysis, the car appears that the above-mentioned control of the door lock without any reflection of the failure should have a great relationship with the J85, because the control of the door lock control and remote control to receive, and drive the door lock the implementation of the motor Are based on J85 as the center to complete. By the above "no response" of the fault phenomenon suspected J85 did not work. According to the anti-theft alarm system circuit diagram was checked and found to provide power to the J85 fuse S12 (15A) has been blown. Replace the new fuse, the fuse is not immediately re-fuse, then use the key to lock the door / door operation, the system restored the control of the door lock function. However, when using the key remote control to make the vehicle into the lock door anti-theft state and found the burglar alarm horn H8 without any sound, and four alarm lights L1 ~ L4 always flashing, by observing the four door lock button can see , The locks are already locked.
    From this, the control of the door lock circuit has been normal, but there have been new failures. Under normal circumstances, the use of remote control lock door / door, the alarm lights and alarm speakers should be short-term shiny and sound, to enter the anti-theft and anti-theft relief response, and this time the speaker does not ring, the alarm light kept flashing , Obviously there is another fault in the alarm system circuit. Maintenance personnel decided to solve the alarm horn H8 (H8 for the car basin-shaped signal horn) does not ring the problem, the demolition of the wiper bar linkage mechanism after the alarm horn and found the speaker has been fever, maintenance personnel suspected to J85 power supply fuse S12 fuse Is caused by the H8, indicating that the warning lights flashing constantly, the alarm speaker has been power, but the speaker has no problem sound. Replace the new speaker, and then open the door / lock the door check operation, the speaker issued a "beep" alarm sound, four alarm lights kept flashing.
    At this time the phenomenon and J85 into the alarm state, but then 4 doors, engine hatch covers and luggage compartment cover has been closed. There are several possible causes of failure: ① J85 is faulty. ② burglar alarm trigger line is faulty. ③ A gated switch (F1 ~ F6) or ultrasonic sensor (G209) is faulty. Maintenance personnel to check one by one, through the multimeter to check the engine compartment cover control switch F1 normal state, F1 to J85 lines are not short-circuit ground, which can be ruled out F1 failure.