Servo Unit

Servo units are electromechanical actuators controlling valve or linkage positions in response to electronic control unit (ECU) commands. Predominantly found in modern transmissions for automated shifting, they are also utilized in throttle bodies, exhaust gas recirculation (EGR) systems, and some braking systems. These units integrate a DC motor, gear train, position sensor (typically a potentiometer or Hall-effect sensor), and control circuitry within a single housing. Operation relies on pulse-width modulation (PWM) signals from the ECU to precisely position internal components. Key specifications include voltage requirements, torque output, and sensor resolution, impacting shift quality or system performance. Failure modes commonly involve motor burnout, gear train wear, or sensor malfunction, detectable via diagnostic trouble codes (DTCs).