P0442 on a 2015 Ford F 250 Supercab

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 2015 Ford F 250 Supercab

Ranked from 296 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Fuel tank filler neck or EVAP line corrosion/leak near the tank
Medium severity
Owners report a rusted-through fuel line and a severe leak at a fitting on top of the tank; since the EVAP monitor pressurizes the tank/lines, any breach there sets a leak code.
Reported in 2 NHTSA complaints
Parts:fuel tank filler neck EVAP line
2
Cracked fuel filter housing allowing vapor/fuel escape
Medium severity
A repeatedly cracking upper fuel filter housing lets fuel odor/vapor escape near the tank/supply lines, which can be picked up by the EVAP monitor.
Reported in 1 NHTSA complaint
Parts:fuel filter housing
3
Fuel line leak/fitting failure with fuel odor
Medium severity
A reported fuel odor while driving with rapidly falling indicated range points to a small supply-side leak that can also compromise EVAP system integrity.
Reported in 1 NHTSA complaint
Parts:fuel line
4
Loose or worn gas cap
Low severity
A cap that won't seal is the single most common cause of a small EVAP leak code and is the first thing to check.
Common cause
Parts:gas cap
5
Cracked EVAP line
Low severity
Rubber or plastic EVAP lines harden and crack with age/heat-cycling, especially near the tank or engine bay.
Common cause
Parts:EVAP line
6
Purge or vent valve failure
Low severity
A stuck or leaking purge/vent solenoid breaks the seal the PCM needs to test the system and reads as a leak.
Common cause
Parts:purge valve vent valve
7
Charcoal canister crack
Low severity
A cracked canister housing leaks vapor and fails the small-leak monitor.
Common cause
Parts:charcoal canister

Part links go to Amazon search results for this vehicle. As an Amazon Associate, WrenchConnect earns from qualifying purchases — always confirm fitment for your exact trim and engine before ordering.

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.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light