P2A73Alternative Fuel Hydraulic Fuel Pump Select Valve Control Circuit High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2A73 signals that the select valve control circuit sits at a higher voltage than the commanded state allows. Typical faults are an open coil or broken wire on a low-side driven valve, which leaves the line at supply voltage, or a short to battery voltage that the output cannot pull down. The valve then stays in its spring-return position, so hydraulic flow keeps going to one tank pump whatever the command. On a multi-tank LNG truck the second tank may never be used, and the engine runs short of gas although LNG remains on board. Caterpillar's patent shows such a valve shifted by an actuator under controller command. No manufacturer publishes P2A73. Check coil resistance, the connector and the supply wire.
- What you may notice
- Check engine light on
- Second LNG tank not used, range clearly shorter
- Gas supply stops although fuel remains
- Likely causes
- LikelyValve coil or control wire open
- PossibleControl wire shorted to battery voltage
- RareCorroded connector pins with very high resistance
- 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: €150 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.