P2451EVAP System Switching Valve Stuck Closed
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- P2451 is the reverse fault of P2450: the evaporative system switching valve will not open when commanded, so vapor or test pressure cannot pass where the system expects it. It shows up mainly on vehicles with a sealed, pressurized fuel tank, such as plug-in hybrids. Mazda's CX-90 and CX-70 PHEV can set it together with P0451, P2422 and P0441; the bulletin suspects the tank pressure sensor or the tank shutter valve and replaces the shutter valve plus the vapor hose that carries the tank pressure sensor. Ford's C-MAX and Fusion hybrids and Energi models listed P2450 and P2451 in a bulletin warning that a software conflict could falsify a pinpoint test unless the fuel door was opened at a set step. A blocked valve can also keep the tank from depressurizing before refueling. Circuit faults of the valve are P2418 to P2420.
- What you may notice
- Malfunction indicator lamp on
- Fuel door or refueling release slow or not working on sealed-tank hybrids
- Likely causes
- LikelyTank shutter or switching valve stuck closed
- PossibleFuel tank pressure sensor giving wrong values to the monitor
- RareSoftware or test-sequence issue (fuel door handling on some hybrids)
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €100 – €600
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.