What causes a P0455 code?

Common causes: Loose / missing fuel cap; Damaged filler neck; Disconnected EVAP hose; Failed vent valve.

What are the symptoms of a P0455 code?

Typical symptoms: CEL; Fuel smell sometimes.

Yes — this code is generally safe to drive with, but address it soon to avoid escalation. Estimated repair: $5-$300.

OBD-II Code · Powertrain

EVAP System — Large Leak Detected

low severitySafe to drive$5-$300

EVAP system large leak — usually missing or loose gas cap.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: loose / missing fuel cap.
Cost & scope. $5-$300
If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.

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