P0455: The Code That Might Just Be Your Gas Cap

A “large EVAP leak” sounds expensive. Sometimes it is a $15 cap — and sometimes it is not.

The cheapest diagnosis in the book, then the real one

P0455 means the fuel vapor system will not hold pressure. The number-one cause is a loose, cracked or missing gas cap — tighten or replace it, clear the light over a few drive cycles, done. When the cap is not it, a smoke machine finds the real leak: cracked EVAP hoses baked by heat, a failed purge valve, a rusty filler neck. Nobody should buy parts for an EVAP code without a smoke test first.

Quick tips

Click the cap tight after every fill-up — no-cap fills set this code
The light takes several drives to clear itself after fixing the cap
Fuel smell in the driveway plus this code = get it smoke-tested

Need hands on the car instead of more reading? VIPCANIC comes to your driveway anywhere in the South Bay, 24 hours a day — call (310) 340-6775.

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P0455: The Code That Might Just Be Your Gas Cap

The cheapest diagnosis in the book, then the real one

Quick tips

Stranded, stuck, or just done with repair shops?