Output Shaft Speed (OSS) Sensor
WARNING: This page is about a different car, the 2002 Ford Econoline. However, it is still accessible from the selected car via links, so may be relevant.
The output shaft speed (OSS) sensor is a magnetic pickup, located at the output shaft ring gear, that sends a signal to the powertrain control module (PCM) to indicate transmission output shaft speed. The OSS sensor is used for torque converter clutch (TCC) control, shift scheduling and to determine electronic pressure control (EPC).