P0442 on a 2019 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 2019 Chevrolet Silverado 1500

Ranked from 1,035 NHTSA owner complaints filed for this vehicle.

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1
Canister purge valve failure
Medium severity
One owner reports the purge ("purge pump") valve failing three separate times, alongside catalytic converter and check-engine issues; a purge valve that won't seal fails the EVAP monitor.
Reported in 1 NHTSA complaint
Parts:purge valve
2
EVAP vent valve/solenoid circuit fault
Medium severity
One owner's scan tool logged a recurring P0499 (EVAP vent valve/solenoid circuit high) alongside the leak code; a vent valve that can't close prevents the system from sealing for the self-test.
Reported in 1 NHTSA complaint
Parts:vent valve solenoid
3
Fuel pump control module (FPCM) fault blocking EVAP canister venting
Medium severity
One owner's CEL was traced to the fuel pump control module, which their shop stated was preventing the EVAP system from venting fuel vapors properly; GM has recalled related FPCM hardware on other model-year trucks.
Reported in 1 NHTSA complaint
Parts:fuel pump control module
4
Damaged/broken fuel filler cap hardware
Low severity
One owner found the spring-loaded fuel cap flap mechanism broken and falling into the filler neck, which would prevent the cap/flap from sealing properly.
Reported in 1 NHTSA complaint
Parts:fuel filler cap
5
Cracked or split EVAP hoses/lines
Medium severity
Rubber and plastic EVAP lines running from the tank to the canister and purge valve harden and crack with age/heat; smoke-test the system to pinpoint the leak.
Common cause
Parts:EVAP hose
6
Cracked charcoal canister
Low severity
A physically cracked canister housing cannot hold pressure/vacuum during the self-test; usually found only with a smoke machine.
Common cause
Parts:charcoal canister
7
Corroded or rusted fuel filler neck
Medium severity
Rust-through at the filler neck (common on trucks that see road salt) breaks the seal to the cap or vent hose; inspect the neck where it meets the tank.
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.

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Matching symptoms

Check Engine Light