P0455 on a 2019 Chevrolet Traverse

P0455 means the EVAP system failed a leak check badly enough that the computer sees a large leak or no pressure/vacuum change.

Not your vehicle? See general P0455 info.

Most common causes on the 2019 Chevrolet Traverse

Ranked from 399 NHTSA owner complaints filed for this vehicle.

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1
Failed/leaking EVAP purge valve (canister purge solenoid) stuck open
Medium severity
The same purge valve that fails repeatedly on this model (replaced 2-3 times on individual vehicles) can stick open and produce a large, easily-detected EVAP leak.
Reported in 7 NHTSA complaints
Parts:purge valve purge valve solenoid
2
Cracked or leaking EVAP fuel vapor canister
Medium severity
A smoke test on one of these vehicles traced a large EVAP leak directly to the fuel vapor canister.
Reported in 1 NHTSA complaint
Parts:EVAP canister
3
Loose, missing, or improperly seated gas cap
Low severity
A large EVAP leak code is most often a gas cap left loose or off entirely; this is the first thing to rule out.
Common cause
Parts:gas cap
4
Cracked, disconnected, or chafed-through EVAP hose/line
Medium severity
A fully disconnected or badly cracked line produces enough open leak area to trip the large-leak monitor rather than the small-leak one.
Common cause
Parts:EVAP hose
5
EVAP canister vent valve (vent solenoid) stuck open
Medium severity
A vent valve stuck fully open prevents the system from ever sealing, which the monitor reads as a large leak.
Common cause
Parts:vent valve solenoid
6
Rusted or corroded fuel filler neck
Low severity
Perforated filler-neck corrosion produces a large enough opening to fail the gross-leak test.
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. P0455 on your car still needs shop confirmation before any repair.

Common symptoms

Check engine light
Fuel smell
Usually no performance issue
Failed emissions readiness

What to check before replacing parts

Check the gas cap first

Look for: A loose, missing, or cross-threaded cap is by far the most common cause of a large EVAP leak code — if it doesn't click to full tightness or the seal is cracked, that's very likely the whole fault.

Inspect visible EVAP hoses

Look for: A large leak is often obvious: a hose disconnected at a fitting, split open, or chewed through (rodent damage is common) rather than a hairline crack.

Command the purge and vent valves with a scan tool

Look for: A valve that doesn't respond at all when commanded open/closed, or stays open when it should seal, prevents the system from holding pressure/vacuum and reads as a large leak.

Smoke-test the system

Look for: With a large leak, expect an obvious plume of smoke or a clearly audible hiss at the fault location — it should be easy to spot compared to a small-leak diagnosis.

Inspect the canister and filler neck

Look for: A cracked charcoal canister housing or a corroded/rusted-through filler neck (common on older vehicles) can leak enough to prevent the system from ever holding vacuum.

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

Matching symptoms

Check Engine Light