P2A90Alternative Fuel Pump C 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
- P2A90 marks pump C of the alternative fuel system as delivering too little. A third pump may belong to a further tank or, in Caterpillar's design US10060421B2, be one of several pumping elements driven in sequence. Besides wear, cryogenic pumps have a typical weakness that Caterpillar's patent US9228574B2 describes: if the liquid at the inlet has warmed enough to form vapour, the pump cavitates and delivery stops, so centrifugal designs need a positive feed pressure. Short bursts of poor output after long parking, with warmer LNG in the tank, fit this picture; a permanent shortfall points to worn parts. The pump diagnosis in US20080302111A1 explains how a slow pressure rise reveals the loss. No manufacturer publishes P2A90; P2A87 to P2A8A cover pump C's stroke valve.
- What you may notice
- Warning lamp on
- Weak pull or hesitation shortly after a long stop
- Gas pressure recovers slowly after heavy acceleration
- Likely causes
- LikelyVapour at the inlet of pump C after warm soak, causing cavitation
- PossibleWorn seals or valves in pump C
- RareClogged inlet strainer or filter ahead of pump C
- 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.