P0455 on a 2016 Chevrolet Colorado

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 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 large vapor/fuel leak
High severity
One owner's truck lost its entire tank of fuel through a failed line/connection at the fuel pump while driving, with gas fumes overpowering the cabin -- a leak large enough to fail the large-leak EVAP monitor outright.
Reported in 2 NHTSA complaints
Parts:fuel line
2
Known EVAP purge/vent valve defect on this platform
High severity
An owner reports the same EVAP-valve failure GM recalled on 2017-2020 Colorados/Canyons occurring on their uncovered 2016 truck.
Reported in 1 NHTSA complaint
Parts:purge valve vent valve
3
Loose, damaged, or missing gas cap
Low severity
A cap that fails to seal at all is a classic cause of a large-leak EVAP code.
Common cause
Parts:gas cap
4
Split or disconnected EVAP hose
Medium severity
A hose that has come off a fitting or split open produces a leak large enough to fail the large-leak test quickly.
Common cause
Parts:EVAP hose
5
Vent valve stuck open
Medium severity
A canister vent valve that won't close prevents the EVAP system from ever holding pressure/vacuum during the monitor's test.
Common cause
Parts:vent valve
6
Cracked fuel tank
Medium severity
Physical tank damage produces a large, continuous vapor/fuel leak.
Common cause
Parts:fuel tank

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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