Suspension Control - Speed Sensitive Suspension (SSS)

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The control module regulates the amount of steering assist at a given vehicle speed by driving the steering assist solenoid valve with the correct PWM duty cycle. The amount of steering assist decreases with increasing duty cycle.

The control module constantly monitors the steering assist solenoid valve PWM drive for correct activity. At times, the control module expects the output to be low ('OFF'). At other times, the control module expects the output to cycle between high and low levels. If the expected level or cycling is not detected, the control module stores error Code 35, activates the 'SERVICE RIDE CONTROL' message and de-activates the steering assist drive.

Recovery of the steering assist output fault will occur if normal activity is detected after a 30 second delay.

TEST CONDITION(S)

The control module monitors the steering assist solenoid valve (Speed-Sensitive steering solenoid valve) PWM drive (pin 'D15') for high voltage ('ON') and low voltage ('OFF') levels.

FAILURE CONDITION(S)

If output drive activity is not correct, the output drive is unable to function as intended, due to a short or open circuit condition or a Control Module or solenoid valve fault.

ACTION TAKEN

Set Code 35, turn 'ON' 'SERVICE RIDE CONTROL' message. Disable steering assist Output. Attempt to recover once every 30 seconds.

NOTES ON FAULT TREE

1. Refer to 'Notes on Intermittents'. Notes on Intermittents

FOR SPEED-SENSITIVE STEERING ASSIST SOLENOID VALVE SERVICE, REFER TO STEERING Steering