P0442 on a 2016 GMC Yukon

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 GMC Yukon

Ranked from 265 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Chafed or leaking fuel line near the tank
High severity
An owner found the fuel supply line near the top of the tank had chafed through and was leaking, producing a fuel smell consistent with a small leak in that area.
Reported in 1 NHTSA complaint
Parts:fuel line
2
Underlying fuel system leak producing fuel odor
High severity
A separate owner reported a fuel pump leak and gasoline smell with the check-engine light cycling, consistent with a fuel-side leak feeding the EVAP system.
Reported in 1 NHTSA complaint
3
Loose, worn, or missing gas cap
Low severity
The single most common small-leak trigger; an improperly seated or cracked cap seal fails the EVAP leak test.
Common cause
Parts:gas cap
4
Purge valve stuck open or leaking
Medium severity
A leaking purge solenoid lets outside air into the system during the EVAP monitor test; listen for the valve clicking during scan-tool self-test.
Common cause
Parts:purge valve
5
Vent valve / canister vent solenoid failure
Medium severity
A vent valve that won't seal fully allows a small, steady leak; command it closed and pressure-test the system.
Common cause
Parts:vent valve
6
Cracked charcoal canister
Medium severity
Age and heat crack the plastic canister housing, creating a persistent small leak.
Common cause
Parts:charcoal canister

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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