What does code P0455 mean?

P0455 — Large EVAP leak detected — fuel vapors escaping to atmosphere rather than being processed. Big leak, easier to find. Belongs to the powertrain.evap system. Severity: warning.

What are the common causes of P0455?

Fuel cap loose or damaged seal — 80% of cases, code clears after tightening; EVAP hose crack — often in engine bay from heat cycles; Purge valve stuck open; Vent valve won't close during pressure test; Cracked or disconnected canister

Can I drive with code P0455?

Limited: reaching the nearest workshop is fine, but avoid long trips. May progress into a more serious fault.

How do I diagnose P0455?

Read the code and freeze-frame with a scanner, check related-system errors, inspect the components listed (wiring, connectors, sensors). See the "How to diagnose" section above for the full step-by-step.

How do I clear code P0455?

The code can be cleared via an OBD-II scanner (e.g. ELM327 + the Car Diagnostics app): plug the adapter into the OBD port, go to Errors → Clear. If the underlying cause isn't fixed, the code will return within a few drive cycles.

OBD-II Code P0455 — Car Diagnostics Platform

What it means

Common causes

Fuel cap loose or damaged seal — 80% of cases, code clears after tightening
EVAP hose crack — often in engine bay from heat cycles
Purge valve stuck open
Vent valve won't close during pressure test
Cracked or disconnected canister
Corroded tank-to-canister line — road salt damage on undercar sections
Faulty Fuel Tank Pressure sensor giving wrong test readings

How to diagnose

01
Read all stored and pending codes with an OBD-II adapter — get the full picture, not just the one code.
02
Capture freeze-frame data (RPM, coolant temperature, engine load) at the exact moment the code triggered.
03
Inspect the named subsystem with our app's AI explanation — get vehicle-specific causes for your make, model and year.

Decode P0455 on your actual car

Plug in an OBD-II adapter and get an AI-powered diagnosis tailored to your vehicle make, model and year — in 30 seconds.

Try the demo