EVAP Very Small Leak

Inspect the gas cap seal

Look for: A seal that looks fine at a glance but is slightly hardened, nicked, or not seating evenly can leak just enough to trip this code — replace the cap if there's any doubt, since it's cheap and the most common cause.

Smoke-test the EVAP system

Look for: This is the smallest leak class — expect to need a smoke machine with dye/UV light and a very close inspection; a very small leak may show only a faint trace of smoke or dye at one seam or fitting.

Check purge valve sealing

Look for: Even a very slight seep past the purge valve when it's commanded closed is enough to fail this test — a valve that holds pressure everywhere else but leaks down slowly over time points to the valve itself.

Inspect the filler neck

Look for: Surface rust or pinholes on the filler neck or its seal to the tank can leak enough vapor to fail only the strictest leak threshold, without any noticeable fuel smell.

Inspect the canister and small hoses

Look for: A hairline crack in the canister housing or a small vacuum-line-sized EVAP hose that has hardened and cracked with age is a common source of a leak too small to smell or see without smoke/dye.