Steering System - 1500: Description: Notes
DESCRIPTION
The Electric Power Steering (EPS) consists of the following components:
| 1. | Refer to EPS RACK AND PINION STEERING GEAR . |
| 2. | Refer to INSTRUMENT PANEL CLUSTER (IPC) . |
| 3. | Refer to STEERING COLUMN CONTROL MODULE (SCCM) . |
| 4. | Refer to BODY CONTROL MODULE (BCM) . |
| 5. | Refer to STEERING COLUMN . |
OPERATION
The standard equipment EPS system provides variable assist to the driver according to driver inputs and the vehicle speed while performing system diagnostic tests and providing this information to the vehicle electrical system. The SCCM has a Steering Angle Sensor (SAS) which transmits the direction and the angle information on the Controller Area Network-Chassis (CAN-C) or Controller Area Network-Interior High Speed (CAN-IHS) bus networks. The SCCM has primary and backup microprocessors with different software algorithms that provide Cyclical Redundancy Checks (CRC) to confirm the SAS position. The EPS warning lamp is used to visually indicate a fault status of the EPS system to the IPC.
The EPS system is a dry gear system. The EPS system does not contain any hydraulic components such as:
- Belt-driven hydraulic pump.
- High-pressure hydraulic hoses.
- Power steering fluid.
The EPS system will not experience a hydraulic leak. If fluid is detected at the front of the vehicle, on or near the steering gear, investigate other systems.
Turning of the steering wheel is converted into 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 vehicle's front wheels.
Power assist steering is provided by an electric motor and module connected to the steering gear. The EPS system provides variable assist for steering maneuvers based on several inputs:
- Steering wheel position and rate of movement from SAS.
- Steering wheel torque from torque sensors in the EPS rack and pinion steering gear.
- Vehicle speed received from the Anti-lock Brake System (ABS) module.
The EPS rack and pinion steering gear is not serviceable and is replaced as a complete assembly. The inner and outer tie rods and the tie rod bellows are serviced separately from the EPS rack and pinion steering gear.
Manual steering control of the vehicle can be maintained if power steering assist is lost. However, under this condition, steering effort is significantly increased.