When servicing the variable effort steering electronic variable orifice (EVO)/ system, perform the following steps in order. Not following these steps may result in the loss of important diagnostic data. This may lead to difficult and time-consuming diagnostic procedures.

1. Perform a vehicle preliminary diagnostic inspection.
2. Perform a power steering system test. Refer to Power Steering System Test in Power Steering System.
3. Inspect the variable effort steering system. Refer to Variable Effort Steering System Check . If any DTCs are displayed, note the last malfunction that occurred. Diagnose and repair this malfunction first.
4. If no DTCs or mechanical component malfunctions are present, or if the condition 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. If this does not reproduce the malfunction, refer to Intermittents and Poor Connections Diagnosis in Wiring Systems.
5. After all the system malfunctions have been corrected, clear the EVO DTCs and test drive the vehicle.