P0442 on a 2021 Kia Seltos
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 2021 Kia Seltos
Ranked from 346 NHTSA owner complaints filed for this vehicle.
- 1
Fuel system line/fitting leak
Medium severityOne complaint describes a persistent gas smell resolved only after the fuel pump and its gaskets/fittings were replaced, consistent with a small detectable vapor leak.
Reported in 1 NHTSA complaint - 2
Faulty fuel level/tank pressure sensor
Low severityA complaint reports the in-tank sensor failing to detect fuel properly, which can cause the EVAP monitor to flag a false small leak.
Reported in 1 NHTSA complaint - 3
Loose or worn fuel filler cap/seal
Low severityThe single most common P0442 cause; a cap that isn't fully tightened or has a worn seal lets a small amount of vapor escape.
Common causeParts:fuel cap - 4
Cracked or worn EVAP line/hose
Medium severityAge-hardened rubber EVAP lines crack and leak vapor slowly, commonly near the top of the fuel tank or engine bay routing.
Common causeParts:EVAP hose - 5
Purge or vent valve failure
Medium severityA valve that doesn't seal fully allows a small, steady leak the system detects during its leak-check routine.
Common cause - 6
Charcoal canister crack
Low severityA cracked canister housing is a common small-leak source, especially on vehicles exposed to road salt/moisture.
Common causeParts:charcoal canister - 7
Rusted or corroded fuel filler neck
Low severityCorrosion can perforate the filler neck enough to fail the small-leak test without being obvious externally.
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.