Check the gearbox control unit and have it repaired by a defect
All repairs on the gearbox control unit should only be carried out by a competent workshop because this is about the safe operation of the car. In addition, ambitious alternation tests can cause more damage than good results due to the extensive networking of the transmission control unit. The workshops are equipped to test a faulty transmission control unit, the gearbox and the peripherals and can be repaired by a defective control unit.
Transmission control unit in the car
Among the "serviceable spirits", who perform almost unnoticed in the car, is the transmission control unit. In the case of vehicles with automatic or automated transmissions, separate transmission control units (TCU) are used. These transmission control units coordinate, regulate and optimize the drive of the car in a variety of ways. The use of the TCU not only ensures optimum driving safety and increased comfort but also low fuel consumption and lower emissions. Malfunctions and defects in the transmission control unit are quickly and clearly shown because the vehicle drive is directly affected.
If the transmission control unit is defective
The control unit is constantly supplied with data by sensors and so-called actuators. This information is continually evaluated by the TCU for errors, irregularities and disturbances. If the control unit detects problems with the drive, spare and emergency functions are automatically activated, which enable the car to continue to operate. At the same time, the transmission control unit does not operate by itself in the automatic transmission and the direct-shift transmission (DSG). Via the so-called CAN bus (controller area network), the transmission control unit is networked with the other control units of the engine, steering, brakes and ESP.
Signs of the defective transmission control unit
Sometimes it happens that the direct gearbox (DSG) can not be switched to the next higher gear or to the reverse gear. Also conceivable is a thermal change at the gearbox during travel or the call of the geared dead program. Signs of defects around the automatic transmission and the direct gearbox (DSG) are implausible values of the travel sensor, problems with the clutch actuator, permanent error messages on the display (F) and errors with the position regulator. In the worst case, other control units can make problems or the car does not start any more. Troubleshooting and repair require a high degree of experience, in particular knowledge of the data bus systems, a lot of technical know-how in gearboxes and professional equipment.
Repair the transmission control unit
If the gearbox or the drive causes problems overall, an appointment with the expert in the workshop is required. Here, the transmission control unit, the transmission and the periphery are diagnosed. Such a test is usually not particularly complex for the professional, but requires a systematic procedure to reliably delimit the error in the TCU. The basis for the error search are the fault descriptions of the customer as well as the listing of all symptoms that result from the readout of the fault memory. Sometimes a test drive may be required.
Cost of repair of the control unit
The possible cost of repairing the transmission control unit is difficult to quantify in advance, because the type, scope and duration of the repair can be very different depending on the fault. If the test in the workshop actually causes a defect in the transmission control unit, repair of the device is in some cases no longer possible. A workshop is not equipped for the repair of control devices. She passes on such tasks to specialist ECU repairers. These are offered by some control units even in exchange. As the last alternative instead of the repair remains the replacement of the control unit.