Circuit Description
WARNING: This page is about a different car, the 2002 GMC Cab & Chassis Sierra and 2002 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The speed sensor circuit consists of a magnetic induction type sensor (which is the OSS) a VSS buffer module, and wiring. Gear teeth pressed onto the output shaft carrier assembly induce an alternating voltage into the sensor. This signal transmits to the VSS buffer module. The VSS buffer module compensates for various final drive ratios. The VSS buffer module also converts the OSS signal into a 40 pulse per revolution 5-volt DC square waveform signal to indicate transmission output speed.
When the PCM detects a low output speed when the vehicle has a high engine speed in a Drive range, then DTC P0722 sets. DTC P0722 is a type "B" DTC.