What is the function of the vehicle speed sensor (VSS)?

The vehicle speed sensor (VSS) plays a crucial role in modern vehicles by providing real-time data about the speed of the vehicle. This information is integral for two main systems: transmission control and the speedometer.

For the transmission system, the VSS monitors how fast the vehicle is moving, allowing the engine control module (ECM) or transmission control module (TCM) to determine the optimal shift points. This results in smoother shifting, improved performance, and better fuel efficiency, as the system can adjust transmission behavior based on speed.

Additionally, the data from the VSS is used to operate the speedometer, which gives the driver feedback on how fast they are traveling. Thus, without the VSS, accurate speed readings and effective transmission operation would not be possible, making its function essential for both vehicle performance and driver awareness.

The other functions listed do not pertain to the direct responsibilities of the VSS.