Circuit/System Description (without HP5)
WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The power steering control module (PSCM) continuously monitors the torque sensor input and output shaft sine wave frequency signals. As the steering wheel is turned and torsional twist is applied to the steering column shaft, the torque sensors input and output shaft sine wave frequency signals are processed by the PSCM to detect and calculate the steering torque.