Circuit/System Description

WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The transmission turbine speed sensor is a permanent magnet surrounded by a coil of wire that is mounted to the transmission case. This sensor is positioned next to the PTO drive gear or tone wheel that is attached to the 1-2-3-4-5-6 Clutch Piston Housing. The housing rotates with the torque converter turbine so that the gear teeth on the PTO or bars on the tone wheel cross the magnetic field and generates an AC current. The voltage output and frequency generated by the sensor will vary as the gear or tone wheel changes speed. The speed sensor signal wires are twisted to cancel magnetically induced fields. The transmission control module (TCM) changes the speed sensor analog signal into a digital signal. The TCM uses turbine speed for shift control, line pressure and speed ratio calculations.