P0442 on a 2016 Ford Focus Bev

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 2016 Ford Focus Bev

Ranked from 1,137 NHTSA owner complaints filed for this vehicle.

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1
Canister purge valve (CPV) failure/stuck (known Ford recall issue, code P1450)
High severity
By far the dominant reported cause: the fuel tank/canister purge valve fails or sticks, commonly triggering DTC P1450 (fuel tank vacuum) alongside P0442, and causing stalling especially right after refueling; this affects the same Focus population covered by Ford recall campaigns (e.g., 24N07) for the CPV. Confirm with a scan tool EVAP monitor and CPV bi-directional test.
Reported in 20 NHTSA complaints
Parts:purge valve
2
Collapsed or dented fuel tank (secondary to a stuck-closed CPV)
Medium severity
Owners reported the fuel tank collapsing/denting, consistent with a purge valve stuck closed creating excess vacuum in the tank during driving; this both damages the tank and can trip an EVAP small-leak code once the tank shape changes.
Reported in 2 NHTSA complaints
Parts:fuel tank
3
Loose, damaged, or missing gas cap
Low severity
A worn, cross-threaded, or loose-fitting cap seal is a common and easily-checked small-leak source.
Common cause
Parts:gas cap
4
Cracked or deteriorated EVAP vent/purge line
Medium severity
Age-cracked or chafed rubber/plastic EVAP hoses create a small leak path; smoke-test the vent and purge hose runs.
Common cause
5
Charcoal canister crack or saturation
Low severity
A cracked canister housing or one overloaded with fuel from overfilling can leak vapor.
Common cause
Parts:charcoal canister
6
Rusted or corroded filler neck
Low severity
Corrosion at the sealing surface prevents a proper cap seal, especially on higher-mileage/salt-belt vehicles.
Common cause
Parts:fuel filler neck

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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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Matching symptoms

Check Engine Light