TCU

As with a racing bike, the car also has a number of gears that ensure that a certain pulling force is transferred to the wheels at a certain speed. With a bicycle you can see the sprockets at the wheel to be driven. In the car, these gears are hidden in the gearbox. In addition to the manual gearbox, which most cars have, a car can also have an automatic gearbox. The automatic gearbox has been around for a long time. The more recent machines have a semi-automatic gearbox or a robotised gearbox. Technically, this construction is very similar to the manual gearbox, only the clutch and shifting are actually done automatically.

Faulty gearbox?

Cost for repair a TCU

Reman company to repair a TCU

Source

https://en.wikipedia.org/wiki/Transmission_control_unit

http://ken-gilbert.com/wrx/STi_Manual/08.%20MECHANISM%20AND%20FUNCTION/33.%20AUTOMATIC%20TRANSMISSION/13.%20Transmission%20Control%20Module%20(TCM).pdf