Continuously Variable Road Sensing Suspension (Cvrss)

Fig. 58 Code RS0015: RF Damper Actuator Over Current (Part 1 Of 2).:

Fig. 58 Code RS0015: RF Damper Actuator Over Current (Part 2 Of 2).:

DTC RS0015 RF Damper Actuator Over Current (Part 1 Of 2):

TEST CONDITIONS:
The CVRSS control module monitors a hardware feedback mechanism while running a Damper Diagnostic Test Procedure, in which the damper actuator under test is commanded to a fixed PWM duty cycle. The feedback mechanism provides a measurement of the amount of current supplied to the actuator during the test procedure. The Damper Diagnostic Test Procedure is executed for each damper actuator, on average, once every 45 seconds.

FAULT CONDITIONS:
At the conclusion of a Damper Diagnostic Test Procedure the resulting feedback current indicates whether the damper output under test, together with the wiring and attached load, is operating within an acceptable range. If the measured current is too high, the test procedure is repeated. If the measured current is again too high, an over-current fault condition is detected. This fault may be attributed to one or more of the following failure conditions: Damper Drive circuit short circuit to voltage, Damper Return circuit short circuit to voltage, Damper Drive circuit short to Damper Return circuit, Damper Actuator failure, or CVRSS control module drive circuit failure.

ACTION TAKE:
Disable ALL dampers by commanding 0% PWM duty cycle AND disabling the Damper Return circuit . Send message to Powertrain Control Module (PCM) to limit vehicle speed, set fault code, and turn on the "SERVICE RIDE CONTROL" message.

DESCRIPTION:
Once every 45 seconds (approximately), a Damper Diagnostic Test Procedure is individually executed for each damper actuator. During the test procedure, which lasts only 20 milliseconds (mS), the damper drive circuit is energized with a fixed PWM Duty Cycle of 20% (battery voltage applied for 0.1 mS, removed for 0.4 mS,applied for 0.1 mS, etc.). During the test interval the hardware feedback mechanism, internal to the CVRSS control module as part of the damper return circuit, tracks the amount of current which is delivered to the load. If, at the end of the test interval, the measured current is higher than the allowable range for a properly connected and functioning load the test is repeated. If the measured current is again higher than the allowable range the corresponding over-current fault code is set. Whenever this fault condition is active for ANY damper, ALL damper outputs are disabled by commanding 0% PWM duty cycle and by disabling the Damper Return circuits, causing all dampers to be in a full-soft state. Once this fault condition is detected, recovery is attempted only after ignition is cycled off and on.

NOTES ON FAULT TREE:
1. Refer to Intermittant.
2. Clear code. Clearing Diagnostic Trouble Codes