Continuously Variable Road Sensing Suspension (Cvrss)

Fig. 63 Code RS0026: RR Damper Actuator Under Current. (Part 1 Of 2).:

Fig. 63 Code RS0026: RR Damper Actuator Under Current. (Part 2 Of 2).:

DTC RS0026 RR Damper Actuator Under 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 low, the test procedure is repeated. If the measured current is again too low, an under-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 ground or open-circuit, Damper Return circuit short circuit to ground or open circuit, Damper Actuator failure, or CVRSS control module drive circuit failure.

ACTION TAKEN:
Disable the affected damper actuator by commanding 0% PWM duty cycle. 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 lower than the allowable range for a properly connected and functioning load, the test is repeated. If the measured current is again lower than the allowable range, the corresponding under-current fault code is set. Whenever this fault condition is active for a given corner (LF, RF, LR, or RR), the corresponding damper drive circuit will be disabled by commanding 0% PWM duty cycle, causing the damper to be in a full-soft state. Recovery is attempted approximately once every 45 seconds and whenever ignition is cycled off and on. Upon successful recovery, the "SERVICE RIDE CONTROL" message is cleared, and the damper output returns to normal operation.

NOTES ON FAULT TREE:
1. Refer to Intermittant.
2. Clear codes. Clearing Diagnostic Trouble Codes
3. Service controller must be calibrated.