Automatic Transmission. Input.
A sensor, located on a vehicle's transmission / transaxle and not a part of the ABS system, used to measure transmission / transaxle output or wheel speed.

SPEED SENSOR

Vehicle Speed Sensor
Your vehicle speed sensor sends information to your speedometer and/or your engine’s computer to tell the transmission when to shift. If the speedometer in your 2014 Volvo V60 isn’t working, or there’s a check engine light that accompanies shifting problems, let a Volvo technician examine your vehicle.