OBD-II diagnostic trouble code
P0456Safe to drive

Evaporative Emission System Leak Detected (Very Small Leak)

The most sensitive EVAP leak threshold — often triggered by something as minor as a slightly loose fuel cap or a small amount of wear in a hose fitting.

Get an OBD-II scanner to read codes yourself →
Most searched
Most common OBD-II codes
The check engine codes drivers look up most often, explained.
Powertrain codes
P-Codes
Browse every engine and transmission diagnostic code we cover.
VIN lookup
VIN Decoder
Decode any vehicle's specs and history from its VIN.
Cost calculator
Total Cost of Ownership
See how repair costs like this one add up over years of ownership.
Code names are compiled from open/standardized SAE and ISO references. Explanations, symptoms, causes and fixes are original. Covers generic (P0/C0/B0/U0) codes only — manufacturer-specific codes are planned for a future update.

Frequently asked questions

Can I drive with P0456?

In most cases, yes — P0456 is generally not an urgent safety issue and the car is usually safe to drive for a while. Still, get it checked soon, since the underlying cause can affect fuel economy or emissions the longer it's left.

How much does it cost to fix P0456?

The cost varies too much by cause and vehicle to give a single figure here — a diagnosis will narrow it down.

What causes P0456?

AS
Reviewed by Artyom SemenovAutomotive Editor · Fact-checked by Yauheni Kapliarchuk, Editor-in-Chief
Code names compiled from open SAE/ISO references; explanations and repair guidance are original editorial content
Last verified: 09 Jul 2026 · Our methodology