Powertrain, generic (extended)

P2451 EVAP System Switching Valve Stuck Closed

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

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.

Likely causes

Tank shutter or switching valve stuck closed
Fuel tank pressure sensor giving wrong values to the monitor
Software or test-sequence issue (fuel door handling on some hybrids)

Symptoms

  • Malfunction indicator lamp on
  • Fuel door or refueling release slow or not working on sealed-tank hybrids

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–600
Time0.5–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

evap switching valve

Related codes

P2450P2418P2419P2420P0441

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu.