Michigan State Mechanic Automatic Transmission Practice Exam

A malfunctioning speed sensor can significantly disrupt the performance of an automatic transmission. The speed sensor plays a crucial role in monitoring the vehicle's speed and relaying that information to the transmission control module (TCM). When the speed sensor is not functioning properly, it can lead to erratic shifting patterns. This means that the transmission may shift at inappropriate times, which can cause a rough or jerky driving experience. Additionally, incorrect speed readings may prevent the transmission from adapting appropriately to driving conditions, further compromising performance.

In essence, a faulty speed sensor can result in erratic shifting that affects both the drivability and overall efficiency of the vehicle, making this the accurate choice regarding its impact on automatic transmission performance.