P0455 on a Chevy: Causes, Fixes & Repair Cost

🟢 Low severity · drivable

Safe to drive — this is an emissions leak, not an engine problem, but fix it before your next emissions test.

What P0455 means on a Chevy

On a Chevy, P0455 means the engine computer has detected a large leak in the evaporative emission (EVAP) system, so fuel vapors are escaping. On Chevys, a loose or damaged gas cap is the most common trigger, though a cracked EVAP hose or a faulty vent valve can also be behind it.

Is P0455 common on Chevys?

P0455 appears on Chevys like the Silverado, Equinox, and Malibu, and it's usually a simple problem. Check the gas cap first — it's the cheapest and most common fix — and use a smoke test if the code comes back.

Commonly reported on: Silverado, Equinox, Malibu, Traverse.

Symptoms

Check engine light is on
Possible fuel smell
No driving symptoms
Emissions test failure

Common causes

most common: Loose, missing, or damaged gas cap
common: Disconnected or cracked EVAP hose
common: Faulty EVAP purge or vent valve
less common: Crack in the charcoal canister

How to fix it

Fix	DIY?	Typical cost
Tighten or replace the gas cap	Yes	$10–30
Inspect and reconnect or replace cracked EVAP hoses	Yes	$10–60
Have a smoke test performed to find the exact leak	Mechanic	$50–150
Replace a faulty purge or vent valve	Yes	$30–120