P0442 on a 2012 Ford Focus

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 2012 Ford Focus

Ranked from 3,789 NHTSA owner complaints filed for this vehicle.

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1
Canister purge valve (CPV) failure trapping vacuum in the fuel tank/EVAP system
High severity
This is Ford's own documented defect on this model (NHTSA campaigns 18V735000 and 19V515000; service actions 18S32/19S22/24N07): a stuck-closed purge valve traps excess vacuum in the fuel tank, sets EVAP small-leak/purge codes (several owners report P0443, P0444, P1450), and repeatedly causes stalling after refueling -- by far the dominant pattern across this vehicle's complaints.
Reported in 20 NHTSA complaints
Parts:purge valve fuel tank
2
Cracked or broken fuel filler neck
Medium severity
One owner's fuel filler neck broke, preventing the tank from being filled normally and creating an EVAP-system integrity fault.
Reported in 1 NHTSA complaint
Parts:fuel filler neck
3
Charcoal canister crack
Medium severity
A cracked canister housing is a common small-leak source independent of the purge-valve defect above.
Common cause
Parts:charcoal canister
4
Loose or damaged fuel filler cap
Low severity
The single most common P0442 trigger industry-wide; verify the cap seals and clicks fully before further diagnosis.
Common cause
5
Cracked or perforated EVAP hose
Medium severity
Age- or heat-cracked vapor lines are a common small-leak source not otherwise documented in this batch.
Common cause
6
Rusted or corroded filler neck (general)
Medium severity
Corrosion can perforate the filler neck over years of use, independent of the recall defect above.
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