OBD codes / P0455 / Toyota Tacoma
P0455 on a Toyota Tacoma
Evaporative Emission System Leak Detected (Large Leak)
All Tacoma generations; EVAP hardware is shared across engines.
What P0455 usually means on a Tacoma
P0455 on a Tacoma is a large EVAP leak — the system can't hold vapor pressure. The cheapest and most common cause is a loose or worn fuel cap, so that's always the first check. Trucks also expose the EVAP hardware — charcoal canister, vent valve, and hoses — to more dirt, water, and road salt than a car, so those components fail here too. There's no drivability effect; it just lights the dash and blocks emissions readiness.
Most likely causes on this model
- Loose or failed gas cap
A cap that won't click or has a hardened seal causes many Tacoma P0455s and is a trivial fix.
- Charcoal canister leak
The underbody canister on a truck is exposed to grime and water and can crack or lose its seal.
- Vent valve stuck open
A vent solenoid that won't seal, sometimes fouled by dirt, prevents the system from holding pressure.
- Cracked or damaged EVAP hoses
Underbody lines on a truck take road debris and salt and split with age.
What it costs on a Tacoma
Begin with a genuine Toyota gas cap, which costs only a few dollars. If the leak is in the canister or vent valve, those parts are moderate but mounted underbody where a truck collects grime, so allow for cleanup and access labor. A smoke test finds the leak so you fix it once.
Year, engine and mileage change the answer. Get a diagnosis for your Tacoma — it weighs these causes against your exact configuration and real complaint data.
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Based on widely reported patterns for this model; individual causes vary by year, engine and history. Generic P0455 behavior is covered on the main P0455 page. Confirm with a scan tool before buying parts.