Suspension Control ( Automatic - Electronic ): Description and Operation

The Selective Ride feature allows the driver to select one of three ride settings. The settings, in conjunction with road speed, are used to determine the suspension's damping rate. Damping provided by the shock absorbers, is a measure of resistance to suspension movement.

The Selective Ride Control System consists of six parts:
^ Four Variable Damping Shock Absorbers
^ Four Shock Absorber Actuators
^ The Selective Ride Control (SRC) Module
^ Select Ride Switch
^ Vehicle Speed Sensor
^ "SERVICE RIDE CONTROL" Indicator

The Shock Absorbers provide damping by forcing oil through internal orifices to resist suspension movement. The variable damping feature is provided by changing the size of the orifices. The orifice size is controlled by adjusting a shaft which extends through the top of the shock absorber. The shaft is turned by the actuator, mounted on top of the shock absorber.

Each of the actuators consist of a Damping Adjustment Motor which turns the adjusting shaft, and a Position Feedback Sensor which indicates the position of the shaft.

The Selective Ride Control (SRC) Module receives inputs from the Select Ride Switch, Vehicle Speed Sensor and Position Feedback Sensors. Based on the inputs, the Module then powers the Damping Adjustment Motor to move the required position.

The SRC Module receives power in "RUN," "BULB TEST" or "START." Immediately after Ignition "ON," the SRC Module performs a self-check. If everything is OK, the SRC Module will set the dampers to a 60° valve position. If everything is not OK, the indicator control output is grounded turning on the "SERVICE RIDE CONTROL" Indicator. The SRC Module controls the damper motors by applying battery voltage and ground to the respective damper motor control outputs. The SRC Module can move the damper motors in either direction. The motor range of travel for the damping adjustment while attached to the shock absorber is from 0° to 160°. The SRC Module determines the position of the damper valve by counting ground pulses on the position sensor input from the Actuator position feedback sensors. Once a speed signal has been detected, the SRC Module adjusts the damper valving according to vehicle speed and Select Ride Switch setting ("PERF," "SPORT" or "TOUR"). The damping rate increases with vehicle speed. The SRC Module has the ability to store system trouble codes. These codes may be read by grounding terminal "C" of the DLC and observing the "SERVICE RIDE CONTROL" Indicator.

The system will not read out diagnostic codes while it is moving.