Diagnostic Trouble Code Tests and Associated Procedures

Air Suspension Module Diagnostic Trouble Code (DTC) Chart

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

B1317-B2477 / C1724-C1830:

C1885-C2002 / U0073-U2050:

Clearing DTC 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 C1990, C1991 and C2002 are present, carry out the pneumatic test. The tester will indicate if the vehicle has passed the test.

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 C1990, 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.
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".