Transmission Control Units (TCUs) are electronic modules managing automatic transmission operation within passenger vehicles and light trucks. They receive data from sensors monitoring vehicle speed, engine load, and throttle position to precisely control hydraulic pressure and shift timing. Modern TCUs utilize sophisticated algorithms—often incorporating learning capabilities—to optimize shift quality, fuel efficiency, and adapt to individual driving styles. Key features include solenoid control, torque converter clutch (TCC) regulation, and diagnostic capabilities for transmission faults. Current designs increasingly integrate with powertrain control modules (PCMs) for coordinated operation and utilize CAN bus communication.