Diagnostic Process

When servicing the Speed Dependent Steering Electronic Variable Orifice system (EVO), the following steps should be followed in order. Failure to follow these steps may result in the loss of important diagnostic data and may lead to difficult and time-consuming diagnostic procedures:
1. Perform a vehicle preliminary diagnostic inspection. This should include:
- Inspection of the power steering fluid reservoir for proper power steering fluid level, signs of contamination and for proper power steering type.
- Inspect the EVO Module and system for any wiring damage.
- Inspect the EVO Solenoid, connector and wiring.
- Inspect for poor powering steering pump performance.
- Inspect the power steering gear for leaks, malfunction or poor performance.
- Inspect the vehicle speed system and wiring.
- Inspect the power steering fluid hoses for binding and sharp bends.
2. Perform the "Diagnostic System Check." If any DTCs are displayed, note the last malfunction that occurred. Diagnose and repair this malfunction first.
3. If no DTCs or mechanical component malfunctions are present, or if the failure is intermittent and not reproducible, test drive the vehicle while using the automatic snapshot feature of the Scan Tool. Perform normal acceleration, stopping, and turning maneuvers.
4. Once all system malfunctions have been corrected, clear the EVO DTCs and test drive the vehicle.