Transmission control unit Archives - Transmission Digest
Modern Transmissions & Vehicle Security: Where is the TCU?

Engine-management computers have moved from the passenger compartment to under the hood to the top of the engine to reduce wiring (copper) and assembly costs in vehicles. Many of you may have seen manufacturers even begin to place the transmission control unit (TCU) inside the transmission (Figure 1). I am not aware who was first to use this technology, but I have seen it for many years on Mercedes-Benz vehicles.