Initial Inspection and Diagnostic Overview

1. Verify the customer's concern by operating the steering system while driving to duplicate the condition.
2. Inspect to determine if any of the following mechanical or electrical concerns apply:

Mechanical
- Tire pressure, loose wheels.
- Loose tie rod ends, inner ball joints.
- Loose suspension struts or ball joints.
- Loose universal joints.
- Loose connecting bolts on the column intermediate shaft.
- Loose steering gear assembly.
- Improper drive belt tension.
- Binding or misaligned steering column.
- Power steering pump, fluid level, hose leak or line restrictions.

Electrical
- Open fuses in the fuse junction panel, Fuse 28 (10A), power distribution box Fuse 4 (15A).
- Circuitry and connections.
- Steering wheel rotation sensor.
- Vehicle speed sensor.
- Power steering pump actuator valve.
- Air suspension/electronic variable orifice (EVO) control module.
- Air suspension/steering test connector.

3. If inspection reveals obvious concern(s) that can be readily identified, service as required.
4. If concern remains after the inspection, use Rotunda New Generation Star (NGS) Tester to retrieve diagnostic trouble codes (DTCs). To retrieve DTCs:
- Connect New Generation Star (NGS) Tester to the air suspension/steering test connector on the RH front shock absorber tower.
- Execute Function Test 211; refer to Functional Tests. Record retrieved DTCs.
- Run Auto Test; refer to Auto Test Diagnostics procedure to determine which DTCs are currently being detected.
If the stored DTCs are different than current DTCs, service current DTCs first. If more than one DTC is displayed in stored or current memory, service in the following order:
- 1st-Electrical Faults, DTC 25, DTCs 50 through 95.
- 2nd-Electro-Pneumatic Faults, DTCs 98 and 99.
- 3rd-Courtesy Lamp Switches, DTC 29; Shock Absorber Electronic Steering Sensor, DTC 45.
5. If no diagnostic trouble codes (DTCs) are retrieved, go to the Symptom Chart to continue diagnostics. Symptom Related Diagnostic Procedures
6. If diagnostic trouble codes (DTCs) are retrieved, go to the Air Suspension/Electronic Variable Orifice (EVO) Control Module Diagnostic Trouble Code (DTC) Index to continue diagnostics. Diagnostic Trouble Code Tests and Associated Procedures
7. If the Air Suspension/Electronic Variable Orifice (EVO) Control Module cannot be accessed by the New Generation Star (NGS) Tester, go to Pinpoint Test C. C: No Communication With the Module (Air Suspension/EVO)