The excessive noise generated during the operation of the electronic cooling fan is caused by the aging of the component function or the poor dynamic balance of the fan blade. It is decided to replace the electronic cooling fan. Trouble: According to the driver, during the cooling period of the active air-conditioning electronic control system, sitting in the driving room can hear the "whee" noise announced by the electronic cooling fan when it is working. The sound is loud and annoying. Fault diagnosis and removal: The electronic cooling fan of the car is a stepless speed regulation cooling fan.

    Firstly, confirm the symptoms of the problem, start the engine, press the AC button on the active air conditioner control panel, the air conditioner compressor will operate, and the air blown from the various outlets of the instrument panel is cool, indicating that the air conditioner compressor is operating normally. The electronic cooling fan in front of the condenser starts to work. As the speed of the electronic cooling fan increases, the noise gradually increases, and it can be clearly heard even when sitting in the driving room. The maintenance experience shows that the new electronic cooling fan is installed and tested. After the engine has been running for 10 minutes, the new electronic cooling fan announces the noise again, and there is no improvement in the symptoms. Connect the GTl tester for self-diagnosis, select the 7 series E38 chassis model, double-click the "IHKA Active Constant Temperature Air Conditioning" item in the main menu of the electronic control system diagnosis, and the GTl tester will quickly scan the item, and click "Control" Module function" button, select IHKA electronic control system, query fault information, no fault code storage.

    To test the function of the new electronic cooling fan, the method is as follows: close the incineration switch, turn on the incineration switch, select the "electronic cooling fan" test item in the "component control" function menu of the GTl310 detector, and click the "activate" button. The beginning of the electronic cooling fan has gradually changed from low-speed operation to high-speed operation. Stop after 30s. After repeated tests, it was concluded that the new electronic cooling fan function was outstanding, because the previous operation noise did not appear during the whole test. Exit the "component control" function menu, restart the engine, select the "diagnostic response" function menu, and check the new electronic cooling fan operation data. Click the "Display" button, and the GTl tester displays the new operating data of the electronic cooling fan.