Diagnostic Trouble Code Tests and Associated Procedures

Vehicle Dynamic Suspension

Vehicle Dynamics Module (VDM) DTC Chart

NOTE: Repair all other DTCs before repairing C1726. Repair DTCs C1990 and C1991 last.









Clearing DTCs C1990, C1991, C2001 and C2002

NOTE: Before proceeding with the following steps, make sure that the air suspension system is fully functional. The vehicle must pass the Pneumatic Test and have both ride height sensors calibrated for these codes to clear.

1. Connect the scan tool to the vehicle.

2. If DTC C1990 or DTCs C1991 and C2002 are present, carry out the Pneumatic Test. The tester will indicate if the vehicle has passed the test. Inspection and Verification

3. NOTE: The vehicle must be on a level surface before calibrating the ride height sensors. Failure to follow this instruction will result in system malfunction.

If DTC C1990 or DTCs C1991 and C2001 are present, use the scan tool to manually raise and lower the vehicle to the correct ride height on an alignment machine and calibrate the ride heights. Refer to Ride Height Adjustments Ride Height Adjustments.

4. Using the scan tool, retrieve the DTCs. Verify that all DTCs have been cleared.

5. Drive the vehicle and verify the repair. Verify that the message center does not display "Check Suspension".