Accessing Trouble Codes

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 control module and the Rotunda New Generation Star (NGS) Tester.
- System errors detected by the 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 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.

PROCEDURE
1. Retrieve all diagnostic trouble codes stored in the control module memory by executing Function Test 211; refer to the Function Tests procedure.
2. Run the Auto Test Diagnostics to retrieve diagnostic trouble codes.
3. If the stored DTCs are different from the current DTCs, always service the current DTCs first.
4. If more than one diagnostic trouble code is displayed in either the memory or the current DTCs list, service 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; Shock Absorber Electronic Steering Sensor, DTC 45.
5. Refer to Air Suspension/EVO Control Module Diagnostic Trouble Code (DTC) Index to determine correct Pinpoint Test to begin Diagnostics.

NOTE:
- Refer to diagnosis by symptom to gain additional insight before you begin service.
- Always perform Pinpoint Tests corresponding to the DTC to determine where the fault lies and to service the fault properly.