P0442 on a 2016 Hyundai Tucson Fuel Cell

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 Hyundai Tucson Fuel Cell

Ranked from 1,536 NHTSA owner complaints filed for this vehicle.

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1
Purge control valve failure/stuck
Medium severity
Owner had the purge solenoid replaced along with the fuel pump while chasing an intermittent driveability fault, indicating past purge-circuit trouble on this vehicle.
Reported in 1 NHTSA complaint
Parts:purge valve
2
EVAP-system fault previously confirmed on this vehicle (companion P0455 large-leak code)
Medium severity
One complaint explicitly cites a P0455 EVAP code on this same vehicle, confirming a real EVAP monitor failure history rather than a one-off event.
Reported in 1 NHTSA complaint
3
Fuel/vapor odor reported by an owner consistent with a system leak
Low severity
Owner reported a persistent gas smell inside the cabin alongside other driveability complaints, consistent with an EVAP or fuel-system leak rather than a sensor fault.
Reported in 1 NHTSA complaint
4
Loose, worn, or improperly seated gas cap
Low severity
The most common cause of a small EVAP leak code; check for a cracked seal or cap that doesn't click fully closed.
Common cause
Parts:gas cap
5
Cracked or perished EVAP hoses/lines
Medium severity
Small-diameter EVAP hoses harden and crack with age/heat, producing a small leak that this code is calibrated to detect.
Common cause
6
Charcoal (EVAP) canister cracks
Medium severity
A cracked canister housing leaks vapor and commonly sets a small-leak code; look for physical damage or corrosion.
Common cause
Parts:EVAP canister
7
Rusted or corroded fuel filler neck
Low severity
On vehicles in salt/road-spray climates the filler neck can rust through, creating a slow vapor/liquid leak near the gas cap seal.
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