Vehicle Speed Sensor: Description and Operation

The speed sensor consists of the hall element (2), magnet (3), gear (1), etc. It is installed on transfer or transmission.

As the sensor gear is turned by drive gear on transfer (or transmission) output shaft, the signal voltage changes from high to low (or low to high). Such High / Low frequency increases in proportion with the vehicle speed and is sent to ECM (PCM) as pulse signals. ECM (PCM) uses it as one of the signals to control various devices.