Test C: Vehicle Raises and/or Lowers Too Slowly or Uneven Ride Height
Pinpoint Test C: Vehicle Raises and/or Lowers Too Slowly or Uneven Ride HeightNormal Operation
The air suspension height sensor sends a voltage signal to the vehicle dynamics module (VDM). The output ranges from approximately 4.5 volts at minimum height (when the vehicle is low or in full jounce) to 0.5 volt at maximum height (when the vehicle is high or in full rebound).
When the suspension height sensor indicates that the rear of the vehicle is lower or higher than trim height under normal driving conditions, the VDM will command the air compressor and air solenoid valves to either fill or vent the air springs depending on the input from the 2 height sensors. The air compressor sends the air to the air springs first through the drier then along the air tubes, passing through a Y-fitting and connections, through the air solenoid valves and finally to the air springs.
^ DTC C1726 Air Suspension Rear Pneumatic Failure - With the ignition key in the RUN position, DTC C1726 will be set if the air suspension system attempts and fails to inflate (pump) or deflate (vent) a specified number of times.
^ DTC C2002 Pneumatic Test Failure - This DTC indicates that the Pneumatic Test has failed to complete, possibly due to mechanical or electrical failure of the air suspension system. DTCs C1990 and/or C1991 will also set with this DTC.
This pinpoint test is intended to diagnose the following:
^ Air leak(s)
^ Air tube restricted or leak(s)
^ Air tube(s)
^ Mounting bracket(s)
^ Air compressor drier
^ Air spring solenoid valve(s)
^ Height sensor(s)
^ Air compressor
^ Air spring(s)
^ VDM
