Inspection and Verification

Inspection and Verification

1. Verify the customer concern.

2. NOTE: If the door ajar indicator is illuminated when all the doors, the liftgate and the liftgate glass are closed, the air suspension will not work correctly. Repair the door ajar indicator. Refer to Instrument Panel, Gauges and Warning Indicators.

Visually inspect for obvious signs of mechanical and electrical damage.

Visual Inspection Chart:

3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.

4. NOTE: Make sure to use the latest scan tool software release.

If the cause is not visually evident, connect the scan tool to the data link connector (DLC).

5. NOTE: The vehicle communication module (VCM) LED prove out confirms power and ground from the DLC are provided to the VCM.

If the scan tool does not communicate with the VCM:
^ check the VCM connection to the vehicle.
^ check the scan tool connection to the VCM.
^ refer to Information Bus (Module Communications Network), No Power To The Scan Tool, to diagnose no communication with the scan tool.
6. If the scan tool does not communicate with the vehicle:
^ verify the ignition key is in the ON position.
^ verify the scan tool operation with a known good vehicle.
^ refer to Information Bus (Module Communications Network) to diagnose no response from the powertrain control module (PCM).
7. Carry out the network test.
^ If the scan tool responds with no communication for one or more modules, refer to Information Bus (Module Communications Network).
^ If the network test passes, retrieve and record continuous memory diagnostic trouble codes (DTCs).
8. Clear the continuous DTCs and carry out the self-test diagnostics for the air suspension module.
9. If the DTCs retrieved are related to the concern, go to Air Suspension Module Diagnostic Trouble Code (DTC) Chart. Diagnostic Trouble Code Tests and Associated Procedures For all other DTCs, refer to Body Control Systems (Multifunction Electronic Control Module).
10. If no DTCs related to the concern are retrieved, GO to Symptom Chart. Symptom Related Diagnostic Procedures

Pneumatic Test
This test verifies that the air tubes are connected and that they are not restricted. It also verifies that the air compressor, air compressor vent solenoid and air spring solenoid valves are functioning correctly. This test is used to clear DTCs C1990 and C1991. Verify that the following conditions are met before running the Pneumatic Test.
^ All the doors, the liftgate and the liftgate glass must be closed.
^ The transmission is in PARK.
^ The vehicle speed is less the 10 km/h (6 mph).
^ The ignition switch is in the ON position.
^ The air suspension system is enabled.
^ Battery voltage is greater than 11 volts for the duration of the test.
1. Fulfill the pre-conditions.
2. Install a battery charger for the Pneumatic Test to prevent battery drain.
3. Using the scan tool, run the Pneumatic Test.

Trim Height Test (or Accurate Trim Test)

NOTE: The Trim Height Test is used to verify trim height only. If trim height needs to be adjusted, refer to Ride Height Adjustments.

The trim height test is used to make the vehicle level to within 2 mm (0.08 in) of the calibrated trim height. An accurate trim test should be run before setting vehicle alignment.
The following conditions must be met for the trim height test to run:
^ All the doors, the liftgate and the liftgate glass must be closed.
^ The transmission is in PARK.
^ The vehicle speed is less than 10 km/h (6 mph).
^ The ignition switch is in the ON position.
^ The air suspension system is enabled.
^ Battery voltage is greater than 11 volts for the duration of the test.
1. Fulfill the pre-conditions.
2. Install a battery charger for the Trim Height Test to prevent battery drain.
3. Using the scan tool, run the Trim Height Test.

Self-Test
Verify that the following conditions are met before running the On-Demand Self Test.
^ All doors, the liftgate and the liftgate glass must be closed.
^ The transmission is in PARK.
^ The vehicle speed is less than 10 km/h (6 mph).
^ The ignition switch is in the ON position.
1. Fulfill the pre-conditions.
2. Install a battery charger for the On-Demand Self Test to prevent battery drain.
3. Run the air suspension module On-Demand Self Test.
4. Record all listed DTCs.
5. Retrieve stored DTCs.
6. Troubleshoot any On-Demand Self Test DTCs first.
7. Repeat the On-Demand Self Test and clear DTCs after repairs are completed.