Vehicle Speed Sensor

Vehicle Speed Sensor (VSS) signal is delivered to ECM by No. 1 and No. 2 vehicle speed sensors. See Figure. No. 1 vehicle speed sensor is driven by gear on transmission output shaft, and indicates actual vehicle speed. No. 2 vehicle speed sensor detects transmission output shaft RPM. Gear shift point and lock-up timing are controlled by ECM based on signals from No. 2 vehicle speed sensor and throttle position sensor.