P0442 on a 2016 Chevrolet Colorado

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 Chevrolet Colorado

Ranked from 695 NHTSA owner complaints filed for this vehicle.

Sort by:

1
Fuel line/connection failure at the fuel pump causing a vapor leak
High severity
Two owners had a fuel line come loose/disconnected at the fuel pump, releasing fuel vapor that was noticeable while driving -- a large enough breach to trip the EVAP leak monitor.
Reported in 2 NHTSA complaints
Parts:fuel line
2
Known EVAP purge/vent valve defect on this platform
High severity
An owner explicitly reports the EVAP-valve issue that GM recalled on 2017-2020 Colorados/Canyons occurring on their 2016 truck, which wasn't covered -- the same component defect causing a vapor leak.
Reported in 1 NHTSA complaint
Parts:purge valve vent valve
3
Loose or worn gas cap
Low severity
A cap that doesn't seal is the most common source of a small EVAP leak.
Common cause
Parts:gas cap
4
Cracked or brittle EVAP hose
Medium severity
Age-hardened vapor hoses crack near the canister or tank, letting vapor escape.
Common cause
Parts:EVAP hose
5
Cracked charcoal canister
Low severity
A physically cracked canister housing creates a small, hard-to-find vapor leak.
Common cause
Parts:charcoal canister
6
Rusted or damaged fuel filler neck
Low severity
Corrosion around the filler neck seal is a common small-leak source on higher-mileage trucks.
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.

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

Matching symptoms

Check Engine Light