P2A83Alternative Fuel Pump B Compression Stroke Valve Control Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2A83 reports an open or otherwise faulty control circuit at the compression stroke valve of alternative fuel pump B. Whether a second pump exists depends on the layout: in Westport's patent US8726785B2, two LNG vessels each carry their own hydraulically driven pump, while Caterpillar's multi-element pump splits one unit into several separately switched elements. Either way, pump B's valve no longer admits drive oil, and its share of LNG delivery is lost. On a two-tank truck this can leave fuel stranded in the tank that pump B serves. The meaning of the letter B is not public, and no manufacturer documents P2A83. Where the valves are identical, swapping a connector with a neighbour shows whether the fault follows the coil.
- What you may notice
- Warning lamp on
- LNG in one tank cannot be used
- Reduced power under high load
- Likely causes
- LikelyOpen wire or loose connector at valve B
- PossibleSolenoid coil of valve B open
- RareOutput stage for valve B faulty
- 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 – €1,500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.