DESCRIPTION
Automatic Ride Control (ARC) allows driver to select firm (sport) suspension or automatic ride control. The system consists of sensors (for brakes, vehicle speed, steering and acceleration), which relay information about driving conditions to a control module. (Scheme 1)
The same control module also controls the Electronic Variable Orifice (EVO) steering system.
The ARC/EVO control module adjusts vehicle ride from soft to firm during periods of heavy braking, high speed driving, hard cornering, rapid acceleration and supercharger boost. The green FIRM RIDE light on instrument panel will glow when system is in firm condition.
Scheme 1
OPERATION
The ARC selector switch is located on center console. When driver selects FIRM RIDE mode, the control module signals actuators on each shock absorber to adjust to a firm ride. The actuators adjust to a softer ride in AUTO mode.
System automatically switches to FIRM RIDE mode during severe conditions
- Brake system pressure of more than 400 psi (28.1 kg/cm 2 ).
- Speeds of more than 83 MPH.
- Cornering of more than 0.35 G. lateral acceleration ("G" force).
- More than 90 percent of full throttle.
- Rapid acceleration or supercharger boost.
The ARC system returns to automatic dampening a few seconds after vehicle speed, braking and cornering return to normal. FIRM RIDE light will flash to indicate system malfunction.
The EVO system uses varying current from ARC/EVO module to control fluid pressure to actuator/spool valve. This variable assist is dependent on steering wheel speed of rotation. The system provides full assist at low speed (parking lot maneuvers) and minimal assist at high speeds. This improves road feel and directional stability. Full power steering assist returns during evasive maneuvers.
The steering wheel rotation sensor (photo cell) measures wheel rotation and relays information to control module for EVO actuator changes. The ARC/EVO control module is located on module package tray in trunk behind driver side of back seat. During system malfunction, the EVO system will always provide full power steering assist.
FIRM RIDE Light Operation
- Turn ignition off. Open trunk, and lower module package tray behind left side of back seat. Disconnect ARC module 60-pin connector.
- Turn ignition on. At ARC module 60-pin connector, connect a jumper wire between pins No. 15 and 60. Observe FIRM RIDE light. If light comes on, fault exists in module circuitry. Go to TEST C3. If light does not come on, fault exists in light control circuitry. Go to TEST C4.