P2A8EAlternative Fuel Pump A 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
- P2A8E reports that alternative fuel pump A no longer delivers what it should, a mechanical or hydraulic fault rather than an electrical one. Such pumps move liquid fuel, typically LNG out of a cryogenic tank. A patent application now held by Cespira, US20080302111A1, shows how a controller can judge them from the delivery line pressure alone: each time the pump is commanded on, pressure has to climb from a lower to an upper set point within a known range of slopes. A clearly flatter rise means lost volumetric efficiency, and a falling pressure means the pump cannot even keep up with the engine. The document names worn piston seals, leaking static seals or check valves, dirt in the fuel and a weak hydraulic drive as causes. No manufacturer publishes P2A8E or its limits.
- What you may notice
- Malfunction lamp on
- Power loss at high load, gas pressure sagging
- Pump runs noticeably longer to refill the accumulator
- Engine switched to reduced output or diesel-only operation
- Likely causes
- LikelyWorn dynamic piston seals in pump A
- PossibleLeaking inlet or outlet check valve of pump A
- PossibleHydraulic drive of pump A delivering too little force or speed
- RareImpurities in the fuel passing the filter and damaging the pump
- 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: €800 – €6,000
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.