Description & Operation
The Variable Effort Steering (VES) system, also referred to as an Electronic Orifice (EVO) steering system, varies the effort required to turn the steering wheel. VES system provides firmer steering (road) feel at higher vehicle speeds and improves directional stability during parking.
As vehicle speed increases, VES decreases the amount of pump pressure applied to steering gear assembly to increase steering effort and improve steering feel by use of a Electronic Brake Control Module (EBCM).
The EBCM can detect a sudden turn (such as in an evasive maneuver) through input from steering wheel rotation sensor, Anti-Lock Brake System (ABS) wheel speed sensors and VES actuator.
VES system consists of an EBCM, VES actuator, steering wheel rotation sensor and ABS wheel speed sensors. EBCM receives inputs from steering wheel rotation sensor and wheel speed sensors. Based on inputs from these sensors, EBCM cycles VES actuator on and off.
When VES actuator is off (de-energized), full pump pressure is allowed to flow through pump's high pressure line outlet, increasing fluid pressure to the steering gear. See Fig 1 . When VES actuator is on (energized), fluid by-passes pressure line outlet and is routed back into pump, decreasing fluid pressure to the steering gear.
If a system fault occurs, EBCM sets a code. Code can be retrieved to diagnose fault. See DIAGNOSIS & TESTING .
| Component | Location | ||
|---|---|---|---|
| Data Link Connector (DLC) | Left Lower Hush Panel | ||
| EBCM | Rear Of Engine Compartment, At Center Dash Panel | ||
| Steering Wheel Rotation Sensor | At Base Of Steering Column | ||
| VES Actuator | At Pump Pressure Line Outlet | ||
| VES Actuator Module | (1) | ||
| Wheel Speed Sensors | Behind Each Brake Rotor | ||
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