What does P0455 mean?
Evaporative Emission Control System — Large Leak Detected
Direct Answer
P0455 means the EVAP system has a significant leak — larger than 0.080 inches — that is allowing fuel vapors to escape into the atmosphere. Like P0442, the gas cap is the first thing to check, but large leaks are more likely to indicate a damaged component rather than just a loose cap.
Common Symptoms
- ✓Check engine light on
- ✓Noticeable fuel smell near gas tank or rear of vehicle
- ✓Failed emissions test
Common Causes
- 01Missing or severely damaged gas cap
- 02Large crack or disconnected EVAP hose
- 03Cracked charcoal canister
- 04Failed or stuck-open vent valve or purge solenoid
- 05Damaged fuel tank filler neck
How to Fix P0455
Inspect and replace the gas cap
A cracked or missing cap causes P0455. Replace with an OEM cap and retest.
Perform a smoke test
Large leaks are often visible as smoke escaping from a cracked canister, hose, or vent valve. A professional smoke test is the fastest diagnosis method.
Inspect the charcoal canister
Located near the fuel tank, the canister absorbs fuel vapors. Physical cracks are visible on inspection.
Frequently Asked Questions
Is P0455 more serious than P0442?
P0455 (large leak) has a bigger fuel vapor release and is more likely to involve a damaged component vs. just a loose cap. But from a drivability and safety standpoint, both are equally harmless.
Estimated Repair Cost
$15–$800
Gas cap: $15–$30. EVAP hose repair: $100–$200. Charcoal canister: $200–$800.
Safe to Drive?
Yes — with caution
Safe to drive. Address it before emissions testing.
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