Initial Inspection and Diagnostic Overview

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical and electrical damage. Refer to the following:
Mechanical
^ Restricted suspension movement
^ Excessive vehicle load
^ Cut, severed, crimped air line(s)
^ Unmounted height sensor
^ Damaged air spring(s)
Electrical
^ Openfuses:
^ Fuse 6 (5A), and Fuse 20 (5A)in fuse junction panel
^ Fuse 4 (15A) and Fuse 15 (50 A) in poker distribution box
^ Loose, corroded, or disconnected connectors
^ Air suspension switch is in the OFF position
^ Damaged solenoid valve(s)

NOTE: If the door ajar indicator is illuminated, when all doors, lift gate and lift gate glass is closed, the air suspension will not work correctly. Repair the door ajar indicator.

3. If the inspection reveals an obvious concern that is readily repaired, correct the concern before continuing with Inspection and Verification.
4. If the concern remains after the inspection, use New Generation STAR (NGS) Tester connected to the data link connector (DLC) to retrieve continuous diagnostic trouble codes (DTCs) and to execute On-Demand Self-Test diagnostics for the air suspension control module.
^ If the On-Demand Self-Test is passed and no DTCs are retrieved, go to the Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures
^ If DTCs are retrieved, go to Air Suspension Control Module Diagnostic Trouble Code (DTC) Index.
^ If the air suspension control module cannot be accessed by the NGS Tester, go to Pinpoint Test Q.