Vehicle Speed Sensor: Description and Operation

Vehicle Speed Sonsor Circuit:

PURPOSE
The sensor is used by the ECU to determine vehicle speed.

LOCATION
The vehicle speed sensor is mounted inside the speedometer assembly.

CONSTRUCTION
The sensor consists of a reed switch that is closed by a rotating magnet in the speedometer.

OPERATION
As the switch rotates, continuity between terminals A and B is interrupted 4 times per revolution. This reference signal is sent to the ECU for determining vehicle speed.