Electric Power Steering Module
The Electric Power Steering (EPS) module (6) is mounted to the EPS rack and pinion steering gear. It is not serviced separately from the steering gear and they both must be replaced as an assembly.
The EPS module contains two microcontrollers operating independently in order to provide full actuation redundancy. The Electric Power Steering (EPS) system provides direction control of the vehicle via interfaces between the hand wheel of the vehicle and the steering knuckle of the front wheels. The system also provides varying assist to the driver according to driver inputs and vehicle speed while performing system diagnostic tests and providing this information to the vehicle electrical system.
Turning of the steering wheel is converted to linear (side-to-side) travel through the meshing of the helical pinion teeth with the rack teeth within the steering gear. The lateral travel pushes and pulls the tie rods to change the direction of the front wheels. Power assist steering is provided by an electric motor connected to the steering column. The EPS system provides variable assist for steering maneuvers based on several inputs, including vehicle speed, Steering Angle Sensor (SAS), and vehicle voltage. The EPS system communicates over the Controller Area Network - Flex Data (CAN-FD) bus. The SAS is internal to the EPS rack and pinion and outputs the SAS angle to other modules via the CAN-FD bus.
Manual steering control of the vehicle can be maintained if power steering assist is lost. However, under this condition, steering effort is significantly increased.
For additional information about the steering system. Refer to DESCRIPTION AND OPERATION .