P0442 on a 2017 Ford Fusion

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 2017 Ford Fusion

Ranked from 1,096 NHTSA owner complaints filed for this vehicle.

Sort by:

1
EVAP vacuum/vent-path fault causing fuel-tank pressure imbalance
Medium severity
Recurring reports of honking/sucking noises from the fuel tank, hard restart after fueling, and stalling at fill-up point to a restricted or leaking vent path rather than a simple cap issue.
Reported in 4 NHTSA complaints
2
Canister purge valve (CPV) stuck open or failed
High severity
One owner had the purge valve replaced three times for the same failure mode, and another owner's mechanic diagnosed a stuck-open purge valve creating excess fuel-tank vacuum.
Reported in 3 NHTSA complaints
Parts:purge valve
3
Loose, cross-threaded, or worn fuel filler cap
Low severity
The single most common trigger for a small EVAP leak code; check that the cap clicks fully and the seal isn't cracked before condemning any other component.
Common cause
Parts:fuel cap
4
Cracked or damaged EVAP canister
Medium severity
A cracked canister housing lets vapor escape past the carbon bed; smoke-test the canister assembly to confirm.
Common cause
Parts:EVAP canister
5
Cracked or brittle EVAP lines
Medium severity
Heat- and age-cracked rubber EVAP lines under the vehicle are a frequent small-leak source; smoke-test the system to pinpoint.
Common cause
Parts:EVAP lines
6
Rusted or corroded fuel filler neck
Low severity
Rust-through of the filler neck creates a leak path that a smoke test will reveal; more common on high-mileage, road-salt-exposed vehicles.
Common cause

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