Initial Inspection and Diagnostic Overview

DESCRIPTION
The air suspension/steering test connector is located in the engine compartment on the front side of the RH front shock absorber tower. This air suspension/steering test connector allows communications between the air suspension control module and the New Generation Star (NGS) Tester.

System errors detected by the air suspension control module are stored as diagnostic trouble codes (DTCs) in the control module memory. A DTC will be retained for the next 80 ignition switch cycles.

When the air suspension control module detects a system error, the air suspension system is disabled for the current ignition cycle. If the condition causing the system error clears up during the current ignition switch cycle, the system will not reactivate.

INSPECTION AND VERIFICATION
1. Verify the customer's concern by operating the computer controlled suspension system to duplicate the condition.
2. Inspect to determine if one of the following mechanical or electrical concerns apply:

Mechanical
- Restricted suspension movement
- Overloaded luggage compartment
- Ball stud brackets

Electrical
- Open fuses
- Power distribution box fuse 4 (15A mini)
- Power distribution box fuse 13 (60A maxi)
- Fuse junction panel fuse 28 (1OA)
- Loose connectors
- Corroded connectors
- Air suspension switch OFF
- Corroded battery terminals

3. If inspection reveals obvious concerns that can be readily identified, repair as required.
4. If the concern remains after the inspection, go to the diagnostic instructions.
5. Retrieve all diagnostic trouble codes stored in the control module memory by executing Function Test 211.
6. Run the Auto Test Diagnostics to retrieve diagnostic trouble codes.
7. If the stored DTCs are different from the current DTCs, always repair the current DTCs first.
8. If more than one DTC is displayed in either the memory or the current DTCs list, repair in the following order:
1st: Electrical Faults, DTC 25, DTCs 50 through 95.
2nd: Electro-Pneumatic Faults, DTC 98 and DTC 99.
3rd: Courtesy Lamp Switches, DTC 29; Electronic Steering Sensor, DTC 45.

Refer to Air Suspension Control Module Diagnostic Trouble Code (DTC) Index to determine correct pinpoint test to begin diagnostics.

Refer to Symptom Chart to gain additional insight before you begin. Symptom Related Diagnostic Procedures

Always perform the pinpoint tests corresponding to the DTC to determine where the fault lies and to repair the fault properly.