The speed sensor of a vehicle is usually located on either the transmission case or the rear differential assembly of production vehicles. Check your vehicle’s service manual or spare parts catalogue before looking for its speed sensor because vehicle speed sensors come in several different designs depending on the manufacturer.
Speed sensors mounted on the transmission case are usually gear driven, while those on the differential assembly use a trigger wheel mounted with the ring gear. Speed sensors are used to measure the rotations of the gear set in the transmission. The sensor data is relayed to the instrument panel of the vehicle and also used as sensor input for the ABS and traction control and suspension systems. Faulty or broken speed sensors are usually responsible for non-functioning speedometers.