The transmission is controlled by an electronic shift system. The BUT processes the input signals. Based on the information received, the BUT controls the hydraulic control system.
The electronic shift system consists of the following components:
- transmission control unit (TCU),
- switching solenoids (SP1 and SP2),
- pressure control solenoid (PCS),
- locking solenoid,
- input shaft speed sensor (ISS),
- output shaft speed sensor (OSS).
- transmission fluid temperature sensor (TFTS),
- park/Neutral Position Switch (PNP).
Park/Neutral Position Switch (PPS)
The Park/Neutral Position (PNP) switch transmits information from the gear shift lever to the starter and ECU.
The PPN switch can start the engine only in the "P" and "N" positions. (Preventing reckless driving).
The PPN switch makes the reverse light come on when reversing.
It is used for the PPN switch when switching the regulator.
The PPN switch transmits information via a combination of the starter circuit and the reverse circuit to the vehicle directly without the ECU
| Component | Function | |
| C1 | Forward clutch | Connects the input shaft and the front sun gear |
| C2 | Straight coupling | Connects the input shaft and the planetary gear carrier |
| SZ | Reverse clutch | Connects the input shaft and the rear sun gear |
| B1 | Leading brake and 2nd brake | Prevents the rear planetary sun gear from turning clockwise or counterclockwise |
| B2 | 2nd brake | Prevents the outer race F1 from turning clockwise or counter-clockwise, thus preventing the rear sun gear from turning counter-clockwise |
| VZ | 1st and reverse brake | Prevents the planetary gear carrier from rotating clockwise or counterclockwise |
| F1 | One-way clutch No.1 | When B2 is in operation, this clutch prevents the rear sun gear from rotating counter-clockwise |
| F2 | One-way clutch No.2 | Prevents the planetary gear carrier from rotating counterclockwise |
| Planetary gear wheel | These gears change the route along which the driving force is transmitted in accordance with the operation of each clutch and brake in order to increase or decrease the speed of the input and output shaft | |