The most common causes are: Loose, damaged, or missing fuel cap (by far the most common cause); Cracked or disconnected EVAP hose; Failed purge valve or vent valve stuck open; Damaged charcoal canister; Leaking fuel filler neck.

How much does it cost to fix P0455?

Typical repairs range from $15–$60 for replace fuel cap up to $250–$700 for replace charcoal canister. Costs vary by vehicle and region.

P0455powertrain

P0455 – Evaporative Emission Control System Tank Detected (gross leak)

What does P0455 mean?

The evaporative emission control (EVAP) system has detected a large leak. The EVAP system captures fuel vapors from the tank and routes them to the engine to be burned instead of escaping into the atmosphere. P0455 means the system could not hold pressure or vacuum during its self-test, indicating a substantial leak.

What causes P0455?

Listed from most to least common:

1Loose, damaged, or missing fuel cap (by far the most common cause)
2Cracked or disconnected EVAP hose
3Failed purge valve or vent valve stuck open
4Damaged charcoal canister
5Leaking fuel filler neck
6Faulty fuel tank pressure sensor

Code breakdown

SystemP — Powertrain

TypeGeneric (standardized SAE / OBD-II code — same meaning across most manufacturers)

SubsystemAuxiliary emission controls

Common symptoms

Check engine light on
No change in drivability in most cases
Occasional faint fuel odor
Failed emissions test

How to diagnose

1Check the fuel cap first. Remove it, inspect the seal for cracks or debris, and reinstall until it clicks. Clear the code and drive for a few days.
2Inspect the filler neck for rust, cracks, or a damaged sealing surface.
3Visually trace EVAP hoses for cracks, disconnections, or rodent damage.
4Smoke-test the EVAP system — this is the definitive method for locating leaks.
5Test the purge and vent valves for correct operation and for being stuck open.

This does not affect how the car drives and is not a safety issue, but it will fail an emissions test and does release fuel vapor. Often the fix is trivially cheap.

Common fixes and estimated costs

Repair	Estimated cost
Replace fuel cap	$15–$60
Replace EVAP hose	$50–$200
Replace purge or vent valve	$100–$350
Replace charcoal canister	$250–$700

Costs are rough US estimates including parts and labor. Actual pricing varies significantly by vehicle, region, and shop rates.

Good to know

Start with the fuel cap — it resolves a large share of P0455 cases for under $50. Note that the code will not clear immediately; the EVAP monitor only runs under specific conditions, so it may take several drive cycles to confirm the repair.

Back to all Powertrain Codes →

This information is provided for general reference only and may vary by manufacturer, model, and year. It is not a substitute for professional diagnosis or repair.