Monitor Description
WARNING: This page is about a different car, the 2004 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
The output speed sensor monitors the output shaft speed. The ECM controls the gear shift point and the lock up timing based on the signals from the output speed sensor and throttle position sensor.
If the ECM detects no signal from the output shaft speed sensor even while the vehicle is moving, it will conclude that is a malfunction of the output speed sensor. The ECM will illuminate the MIL and store the DTC.