Circuit Description
WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The automatic transmission output speed sensor (OSS) provides vehicle speed information to the transmission control module (TCM). The OSS is a permanent magnet generator mounted to the transmission case. The OSS produces an AC voltage as the transmission speed sensor rotor teeth pass through the magnetic field of the sensor. The AC voltage level increases as the speed of the vehicle increases. The TCM converts the AC voltage into a digital signal. The TCM uses the vehicle speed signal to determine shift timing, torque converter clutch (TCC) apply, TCC release, and gear ratio calculations.
When the TCM detects a low output speed and the vehicle has a large engine speed in a drive gear, then DTC P0722 sets. DTC P0722 is a type B DTC.