P2A8FAlternative Fuel Pump B 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
- P2A8F applies to a second alternative fuel pump whose output has fallen short of expectations. Layouts with two pumps usually give each LNG vessel its own pump, a redundancy Westport's documents mention explicitly. In US20080302111A1, a selector valve decides which pump delivers, and once the controller judges one pump degraded it can switch to the other. The difficulty lies in telling a weak pump from an empty tank: Westport's US8726785B2 notes that little drive work per stroke can mean either a nearly empty vessel or a broken component such as the drive shaft. A P2A8F shortly after refuelling therefore points to the pump itself. Pump B may also be the healthy one, so check which tank was active. No manufacturer documents P2A8F or how its letter is assigned.
- What you may notice
- Malfunction lamp on
- Usable range shorter, fuel left in one tank
- System changes to the other tank earlier than usual
- Likely causes
- LikelyWorn seals reducing the delivery of pump B
- PossibleTank served by pump B almost empty, mimicking a weak pump
- RareBroken drive shaft or coupling between hydraulic drive and pump B
- 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.