P0442 on a 2018 Ford F 250 Regular Cab
P0442 means the EVAP system could not hold pressure or vacuum during a leak test, but the leak is small.
Not your vehicle? See general P0442 info.
Most common causes on the 2018 Ford F 250 Regular Cab
Ranked from 382 NHTSA owner complaints filed for this vehicle.
- 1
Stuck EVAP purge valve or fuel-tank vent/check valve
Medium severityOne owner's mechanic traced sputtering and long-crank symptoms to a stuck EVAP purge/check valve letting fuel-line and vapor pressure bleed down overnight — a small, intermittent leak path consistent with P0442.
Reported in 1 NHTSA complaint - 2
Charcoal canister crack or saturation
Medium severityThe same complaint recommends replacing the EVAP canister as part of the fix, consistent with a canister-related leak path from dust/sediment intrusion.
Reported in 1 NHTSA complaintParts:EVAP canister - 3
Loose or damaged gas cap
Low severityA cap that doesn't seal fully is the single most common source of a small EVAP leak code.
Common causeParts:fuel filler cap - 4
Cracked or worn EVAP hoses/lines
Medium severityAge-hardened rubber lines develop small cracks that leak vapor pressure.
Common cause - 5
Rusted or corroded fuel filler neck
Low severityCorrosion around the filler neck seal creates a small vapor leak path.
Common cause - 6
EVAP vent valve solenoid stuck open
Medium severityA vent valve that won't fully close prevents the system from holding vacuum/pressure during the EVAP monitor.
Common causeParts:EVAP vent valve
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These causes are aggregated from NHTSA owner complaints and general repair knowledge — this is not a diagnosis. P0442 on your car still needs shop confirmation before any repair.
Common symptoms
- Check engine light
- Fuel smell near vehicle
- Usually drives normally
- Hard start after fueling in some cases
What to check before replacing parts
Tighten and inspect the gas cap
Look for: A cap that doesn't click to full tightness, has a visibly cracked or flattened seal, or is simply missing is the single most common cause of a small EVAP leak — rule it out first.
Smoke-test the EVAP system
Look for: Because this is a small leak, expect only a thin wisp of smoke or a faint hiss at one spot (a hose, seam, or valve) rather than an obvious cloud — look closely and take your time.
Check purge valve sealing
Look for: A purge valve that doesn't hold vacuum when commanded closed lets a small amount of air bleed through, which the system reads as a leak during its self-test.
Inspect hoses near the tank and engine bay
Look for: Look for small cracks, soft/collapsed spots, or a hose that has pulled loose slightly at a fitting — any of these can leak just enough to trip a small-leak code without an obvious fuel smell.
Verify vent valve operation
Look for: A vent valve that doesn't seal fully when commanded closed prevents the system from holding vacuum during its self-test, which reads as a small leak even with no physical leak in the hoses.
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