What Does a Speed Sensor Do on a Car?

Speed sensors are part of the system that determines the speed of a vehicle.

A speed sensor relays a vehicle's speed to various other systems within the car. These sensors are usually mounted on the transmission or rear assembly.

Speedometer

The speed sensor is most commonly known for relaying information to the speedometer, which informs the driver of the current speed of the vehicle. A faulty speed sensor can cause the speedometer to inaccurately portray the vehicle's speed.

Anti-Lock Brake System (ABS)

The anti-lock brake system uses information from the speed sensor to determine whether a wheel is locked. Not all cars rely on the speed sensor to relay information to the anti-lock brake system; some have dedicated ABS sensors.

Variable Assist Power Steering (VAPS)

Cars with variable assist power steering use information from the vehicle's speed sensor to determine the pressure in the power steering. This regulation is often used at low speeds to aid in sharp or difficult turns.

References

• Engine Light Help: Vehicle Speed Sensor Description & Related Information