Transmission control unit (TCU)
In Mazda vehicles with an automatic transmission, the transmission control unit (TCU) is responsible for:
* Gear shift control
* Monitoring signals from transmission sensors and actuators
* Providing protective functions of the transmission
* Interface with other vehicle control modules (ECM, ABS, ESP, etc.)
The TCU is located either inside the transmission itself or on an adjacent body part. It receives signals from:
* Gear selector
* Vehicle speed sensor
* Engine speed sensor
*Transmission fluid temperature sensor
* Throttle Position Sensor
* Engine control sensors
The TCU uses these signals to determine optimal gear shift points, control transmission hydraulics, and ensure smooth gear shifts.
TCU reprogramming
The TCU can be reprogrammed if:
*Software updates
* Solutions to transmission performance problems
* Individual shift characteristics settings
This can be done using specialized diagnostic equipment that can connect to the TCU via the OBD2 interface.