Ensure coolant temperature sensor is functioning properly before diagnosing fuel pressure control system. See CODE 22 in TESTS W/CODES article in the ENGINE PERFORMANCE Section. Ensure airflow meter is functioning properly before diagnosing fuel pressure control system. See AIRFLOW METER in ENGINE SENSORS & SWITCHES.
Disconnect electrical connector from fuel pressure Vacuum Switching Valve (VSV). Using a DVOM, measure resistance between VSV terminals. Resistance should be 30-50 ohms. If resistance is not within specification, replace VSV.
Using a DVOM, check for continuity between each VSV terminal and ground (outside of VSV). If continuity is present, replace VSV. With electrical connector disconnected, ensure air flows between VSV ports.
Apply battery voltage between VSV terminals. Apply air to port "E". See Fig 1. Air should flow from port "E" to filter. If air does not flow as indicated, replace VSV.

Fig 1: Identifying Fuel Pressure VSV Ports

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Fuel Pressure Control System