Automatic transmission (VW Passat B3)

At the owner's request, the VW PASSAT, in addition to models with diesel engines and a 75 hp petrol engine, can be equipped with an automatic transmission. The automatic transmission has 4 ranges of forward positions that switch automatically.

The automatic transmission is controlled by an electronic control unit. The control unit receives signals from sensors about the position of the gear selector, the oil temperature in the transmission, the speed of the transmission shaft, and also receives information about the instantaneous engine load from the injection system control unit. Using four electromagnetic valves, the control unit controls the process of switching the transmission operating modes. As a result, low fuel consumption, soft switching processes are achieved, and the driving mode can be selected: economical or sporty.

If the input signals are disrupted or the solenoid valves are faulty, a switchover to a temporary program is carried out, and the fault that occurs during the trip is recorded as a code in the memory device and can be later determined using a VW reading device.

To evaluate the performance of the automatic transmission and to correctly search for a fault, experience with such transmissions and knowledge of their operating principles are required. This knowledge can only be acquired through long-term professional experience.