P2A7BAlternative Fuel Hydraulic Pressure Sensor Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2A7B covers a hydraulic pressure signal that is electrically valid but does not fit the operating state. Plausibility can be judged because pressures in the hydraulic drive of an LNG pump follow a known pattern: during a stroke the working side carries load pressure, while the return side stays close to reservoir level until the valve reverses. Westport's patent adds that pressure depends on hydraulic pump speed and on the LNG pressure the pump works against, so the expected values are corrected by table. A value frozen during strokes, a return pressure that climbs along with the supply, or a mismatch with the P2A75 sensor suggests drift, a blocked sensor port or a restricted return line. No manufacturer publishes limits for P2A7B.
- What you may notice
- Warning lamp after several drive cycles
- Irregular pump strokes or reduced power on gas
- Likely causes
- LikelySensor drift or offset
- PossibleSensor port blocked by contaminated oil
- RareRestricted return line or filter raising return pressure
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Workshop only · Usually a job for a workshop.Typical cost: €150 – €2,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.