C1252

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Part 2 Of 2:

CIRCUIT DESCRIPTION
The Continuously Variable Road Sensing Suspension (CVRSS) calculates normal force and transmits a Pulse Width Modulated (PWM) signal to the Electronic Brake and Traction Control Module (EBTCM) via two dedicated data lines, one right, and one left. The EBTCM supplies the pull up voltage. The EBTCM uses this information to detect rough road conditions and allows for more aggressive braking on rough surfaces.

CONDITIONS FOR SETTING THE DTC
The EBTCM measures the PWM duty cycle sent from the CVRSS and checks to see that it is between 10% and 90%. The possible values of duty cycle are 20%, 40%, 60%, and 80%. The CVRSS sends each value twice therefore any normal force value sent to the EBTCM should match either the previous or next normal force value. If either of the above faults are present for more than 5 seconds out of any 10 second period the EBTCM will set a normal force fault.

ACTION TAKEN WHEN THE DTC SETS
^ A malfunction Diagnostic Trouble Code (DTC) is stored.
^ The Stabilitrak rough road performance enhancements are disabled.
^ ABS/TCS/Stabilitrak remain functional.

CONDITIONS FOR CLEARING THE DTC
^ The condition for DTC is no longer present and you used scan tool Clear DTCs function.
^ The condition for DTC is no longer present and you used the On-Board Clear DTCs function.
^ The EBTCM does not detect the DTC in 50 drive cycles.

DIAGNOSTIC AIDS
^ It is very important that a thorough inspection of the wiring and connectors be performed. Failure to carefully and fully inspect wiring and connectors may result in misdiagnosis, causing part replacement with reappearance of the malfunction.
^ An intermittent malfunction can be caused by poor connections, broken insulation, or a wire that is broken inside the insulation.
^ If an intermittent malfunction exists, refer to Intermittents and Poor Connections Diagnosis in Diagrams..


TEST DESCRIPTION
The numbers below refer to step numbers on the diagnostic table.
4. Checks for proper duty cycle.