P0442 on a 2016 Chevrolet Silverado 1500

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 Silverado 1500

Ranked from 792 NHTSA owner complaints filed for this vehicle.

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1
Cracked fuel pump/sending-unit module at the top of the tank
High severity
Four separate service records describe the in-tank fuel pump module's outlet port cracking and leaking in the same spot across multiple VINs - a compromised module breaks the tank's ability to hold vapor pressure for the EVAP leak test.
Reported in 4 NHTSA complaints
Parts:fuel pump module
2
Fuel tank vapor vent leak requiring tank replacement
High severity
An owner's EVAP-leak-detected code was traced by the dealer to the fuel tank leaking at its internal vents, requiring full tank replacement - a direct, vehicle-confirmed small-leak cause.
Reported in 1 NHTSA complaint
Parts:fuel tank
3
Damaged fuel filler neck/spout retaining clip
Medium severity
A worn/broken filler-port retaining clip lets the fuel spout sit loose in the filler neck, which can prevent a proper seal at that end of the vapor system.
Reported in 1 NHTSA complaint
Parts:fuel filler neck assembly
4
Restricted/clogged EVAP vent line causing hard-fill and failed pressure test
Medium severity
A truck that won't accept fuel normally (pump handle clicking off early) despite a TSB calling for tank replacement points to a vent-side restriction that can also cause the system to fail its leak-down test.
Reported in 1 NHTSA complaint
Parts:fuel tank
5
Loose or worn gas cap
Low severity
Still the single most common small-leak source industry-wide, independent of the tank/pump issues seen in this batch.
Common cause
Parts:gas cap
6
Purge or vent valve failure
Medium severity
A purge or vent solenoid that won't fully seal introduces a small, steady leak path.
Common cause
Parts:EVAP purge valve EVAP vent valve
7
Charcoal canister crack
Medium severity
A hairline crack in the canister housing is a common, hard-to-spot small-leak source.
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.

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

Matching symptoms

Check Engine Light