How does Electronic Stability Control (ESC) detect and correct vehicle instability?

ESC compares driver intent (from steering angle and throttle position) with actual vehicle motion (from yaw rate and lateral acceleration sensors). When deviation exceeds thresholds indicating understeer or oversteer, ESC intervenes by selectively braking individual wheels to create corrective yaw moments. For understeer, it brakes the inside rear wheel; for oversteer, the outside front wheel. ESC also reduces engine torque and may integrate with active steering for smoother interventions.