Module, Electric Power Steering (EPSM): Operation

WARNING: This page is about a different car, the 2018 Fiat 500L. However, it is still accessible from the selected car via links, so may be relevant.

NOTE:

All diagnostics must be done through the electric power steering module for the electric power steering system. Refer to DIAGNOSIS AND TESTING . There are no serviceable parts inside the column, module or motor. If any part is found to be defective or needs replacement, the column, motor, and module are serviced as a assembly.

The Electric Power Steering Module (EPSM) uses input signals received from sensors to vary the current to the electric motor for the desired power steering torque. Communication is received and transmitted to the EPSM on the CAN line.

The module outputs the following actions based on input received:

Basic Operation: Based on vehicle speed, assists the column rotation based on driver input to decrease steering effort for the driver.
Variable Servo Steering: When the speed of the vehicle is increased, the module reduces the amount of assistance to the column.
Active Return: The module commands the motor to quicken the steering wheel in returning to the center position after steering.
Damping of Steering Return Oscillations: After a steering manoeuvre, the chassis produces oscillations that the module will then use the motor to try and reduce.
Selectable Power Assistance: Using a driver selectable switch on the control panel, "Normal" will provide assist at medium and high speeds, while "City" provides greater assistance at lower speeds for easier driving and parking.

NOTE:

Whether or not the ECO button is pressed, the driver will experience the same level of assistance: it is the performance of the vehicle that changes; it will be reduced to favor fuel economy.