Chevrolet Equinox Service Manual: Power Steering System Description and Operation (Electronic Power Steering) Hydraulic Steering

K43Power Steering Control ModuleK17Electronic Brake Control ModuleP16Instrument ClusterB137Power Steering Shaft Torque SensorM38Power Steering Motor

The power steering system consists of the following components:

The rack and dual pinion electric power steering system reducesthe amount of effort needed to steer the vehicle utilizing the powersteering control module to control the power steering motor to maneuverthe steering gear. The power steering control module also uses a combinationof the torque sensor, motor rotational sensor, battery voltage circuitand GMLAN serial data circuit to perform the system functions. Thepower steering control module monitors vehicle speed and engine speedfrom the engine control module via the GMLAN serial data circuit todetermine the amount of steering assist needed to steer the vehicle.At low speeds more assist is provided for easy turning during parkingmaneuvers. At higher speeds less assist is provided for improved roadfeel and directional stability.

The power steering control module uses a combination of thetorque sensor, motor rotational sensor, vehicle speed, and calculatedsystem temperature inputs to determine the amount of assist needed.The power steering control module continuously monitors the digitaltorque sensor's torque and index current signals. As the steeringwheel is turned and torsional twist is applied to the steering shaft,the steering input and output shafts are monitored via the torquesignal circuit and then processed by the power steering control moduleto calculate the steering torque. The voltage signals of the motorposition sensor and the digital torque sensor's index current signalare both processed by the power steering control module to detectand calculate the steering wheel angle.

The power steering control module responds to the change inthe digital torque sensor signals as well as the motor rotationalsensor's voltage signals by commanding current to the power steeringmotor. The power steering control module controls the pulse widthmodulated motor drive circuit to drive the 3-phase motor. The powersteering control module and motor assembly is attached to the baseof the steering gear housing and assists the steering gear pinionto maneuver the rack from left to right according to turning the steeringwheel.

The power steering control module has the ability to calculatean internal system temperature to protect the power steering systemfrom damage caused by high temperature. To reduce a high system temperature,the power steering control module will reduce the amount of currentcommanded to the power steering motor, which reduces the amount ofsteering assist. The power steering control module has the abilityto detect malfunctions within the electric power steering system.Any malfunction detected that disables steering assist will causethe SERVICE POWER STEERING message to be displayed on the driver informationcenter.