P2A74Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit Intermittent/Erratic
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2A74 covers brief, recurring faults in the select valve control circuit that clear before a firm low or high verdict. On LNG trucks the valve usually sits near the tank-mounted pump and hydraulic lines, where frame flex, road spray and very cold surfaces around the cryogenic tank stress connectors and insulation. A valve that drops out for a moment can cut hydraulic flow to the working pump mid-stroke; because Westport's control logic recognises the stroke end from pressure changes, such dropouts may also upset pump timing. Typical finds are loose terminals, corroded pins and wiring chafed along the frame rail. No manufacturer publishes P2A74. Wiggle the harness while watching the output status, and check the plug for moisture.
- What you may notice
- Check engine light on, may go out again
- Brief hesitation or pressure dips in gas mode
- Irregular tank changeover
- Likely causes
- LikelyLoose terminal in the select valve connector
- PossibleMoisture or ice in the connector near the cryogenic tank
- PossibleHarness chafed along the frame rail with intermittent contact
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Hard · Usually a job for a workshop.Typical cost: €100 – €900
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.