What causes a P0456 code?

Common causes: Aging fuel cap seal; Tiny hose crack; Failed purge or vent valve seal.

What are the symptoms of a P0456 code?

Typical symptoms: CEL; Often no driveability symptoms.

Yes — this code is generally safe to drive with, but address it soon to avoid escalation. Estimated repair: $20-$500.

OBD-II Code · Powertrain

EVAP System — Very Small Leak Detected

low severitySafe to drive$20-$500

EVAP system very small leak — pinhole-level.

Common symptoms

Likely causes

Where to start

Try the cheapest cause first. Start by checking: aging fuel cap seal.
Cost & scope. $20-$500
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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