Component Tests and General Diagnostics

NOTE: For more information on the pneumatic components, proceed to Air Suspension Pneumatic Diagram. Mechanical Diagrams

1. Connect NGS Tester to the data link connector C228F.
2. Turn the ignition switch to the RUN position.
3. Select the proper vehicle year, model, and engine type.
4. Select 4WAS-AIR SUSP/EVO (4X2 and 4X4) module.
5. Monitor the RHGTSEN PID.
6. Use the active command "LIFT REAR" to lift the rear noticeably higher (should only take about 30 seconds) and turn OFF.

NOTE: If vehicle does not raise at all, inspect for kinks or excessive leaks in all rear air lines and all connectors.

7. Wait a few seconds for the rear air suspension height sensor voltage reading to stabilize. If the rear air suspension height sensor voltage reading does not stabilize (voltage value increases), check for leaks at the air suspension rear air springs. Repair and/or replace as necessary.
8. Open the air suspension rear air spring solenoids with the active command "LR AIRSP" and "RR AIRSP".
9. Wait a few seconds for the rear air suspension height sensor voltage reading to stabilize. If the rear air suspension height sensor voltage reading does not stabilize (voltage value increases), check for leaks and kinks in the air line between the air suspension rear air springs and the air compressor (dryer inlet). Check the air lines for incorrect connection(s) at the air suspension rear air spring(s), union, T-fitting, and the air compressor (dryer inlet). Check rear air springs for leaks and seal between air springs and air solenoid. Repair and/or replace as necessary. If the fault cannot be found, replace the air compressor assembly.