P0442 on a 2022 Ram 1500 Crew Cab

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 2022 Ram 1500 Crew Cab

Ranked from 588 NHTSA owner complaints filed for this vehicle.

Sort by:

1
EVAP vent / fuel-tank valve failure
Medium severity
Dealer identified the fuel tank's EVAP vent valve as faulty (broken fill-side nipple) after the truck refused to accept fuel, calling it a common issue on these trucks.
Reported in 1 NHTSA complaint
Parts:fuel tank vent valve
2
Small EVAP system leak
Low severity
Owner's check-engine light was tied to a documented "small emissions system leak" noted alongside an unrelated fuel-pump fault.
Reported in 1 NHTSA complaint
3
Loose, damaged, or missing gas cap
Low severity
The most common trigger for a small-leak EVAP code.
Common cause
Parts:gas cap
4
Cracked or perished EVAP hose/line
Medium severity
Inspect lines between canister, purge valve, and tank for small cracks or chafing.
Common cause
5
Purge valve stuck/leaking
Medium severity
A purge valve that doesn't seal fully can produce a small-leak code.
Common cause
Parts:purge valve
6
Charcoal canister crack
Low severity
A hairline crack in the canister housing is a common small-leak source.
Common cause
Parts:charcoal canister
7
Rusted/corroded fuel filler neck
Medium severity
Corrosion near the cap seat can create a small leak path.
Common cause

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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.

Rather have a pro handle it? Find a vetted local mechanic.

Matching symptoms

Check Engine Light