P2A75Alternative Fuel Hydraulic Pump Pressure Sensor Circuit
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- In a hydraulically driven LNG pump system the controller watches the oil pressure delivered by the hydraulic pump. Westport's patent US8726785B2 places this sensor in the supply line between the hydraulic pump outlet and the hydraulic drive, using it for three jobs: reversing the drive at each stroke end, spotting an empty tank when peak pressure stays low, and flagging leaks or other abnormal conditions. Caterpillar's design likewise feeds supply and return pressure to the controller to shift its directional valve. P2A75 is the general circuit fault of this hydraulic pump pressure sensor. Without the signal, the pump cannot be cycled correctly and LNG delivery may stop. No manufacturer publishes P2A75; P2A77 and P2A78 cover low and high.
- What you may notice
- Check engine light on
- LNG pump stops or strokes irregularly, gas pressure drops
- Dual-fuel engine runs on diesel only or with reduced power
- Likely causes
- LikelyConnector or harness at the hydraulic pressure sensor damaged
- PossibleHydraulic pump pressure sensor faulty
- RareSensor supply or ground disturbed
- 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 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.