Description & Operation

The Electronic Variable Orifice (EVO) system modulates power steering effort according to vehicle speed and steering wheel rotation rate. System provides full assist at low vehicle speed for light parking effort, and minimum assist at high vehicle speed for improved handling and road feel. Full power steering assist is available for evasive maneuvers. During periods of system malfunction, system will provide full power steering assist at all times.

Diagnostic codes are accessible through service diagnostic connector. EVO system consists of speed and steering sensors, control module, actuator, and interconnecting wiring. Steering wheel rotation sensor and Vehicle Speed Sensor (VSS) send signals to EVO control module, which controls EVO actuator valve on power steering pump.