C1720

CIRCUIT DESCRIPTION
The LR damper actuator is driven by the Continuously Variable Road Sensing Suspension (CVRSS) control module via a method known as Pulse-Width Modulation (PWM). Battery voltage is PWMed (switched on and off) at a high frequency (2.0 kHz), thus controlling the amount of current delivered to the actuator. By controlling the amount of current to the actuator, the CVRSS control module can then control the damping force in the damper. A higher level of damping force is achieved by providing correspondingly higher current levels, relating to higher percentages of PWM duty cycle.
The default damper state (with no battery voltage, and thus no current provided to the attached actuator) is one that provides a minimum damping force.

CONDITION FOR SETTING THE CODE "CURRENT"
The CVRSS control module measures an ON-state feedback voltage greater than a preset fault threshold during a damper diagnostic test procedure.

The CVRSS control module performs a test procedure on each damper actuator approximately every 16 seconds. During this test procedure the damper actuator is briefly energized (ON-state test) and de-energized (OFF-state test). If, twice consecutively, the feedback voltage during the ON-state test is above the fault threshold, the corresponding code is set.

ACTIONS TAKEN WHEN CODE SETS
^ The LR damper actuator will be disabled by commanding 0% PWM duty cycle. (The LR corner of the vehicle will be soft.)
^ The "SERVICE RIDE CONTROL" message will be displayed.

CONDITION FOR CODE TURNING "HISTORY"
When the CVRSS control module no longer senses a short to battery voltage on the damper low-side drive.

HOW TO CLEAR THE CODE
^ Use the scan tool.
^ Use the On-Board diagnostic "CLEAR RSS CODES" feature.

TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
2. Checks for an internal short in the actuator.
3. Checks for short to voltage on the actuator pigtail harness.
4. Checks CVRSS actuator harness for a short to voltage with the actuator disconnected. If voltage is indicated, there is a short to voltage on circuit 1115CR.
5. Checks CVRSS actuator harness for a short between circuit 1114CR and circuit 1115CR.