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P0456

Evaporative Emission System Leak Detected (Very Small Leak)

Moderate severity

This code means your car's computer has found a tiny leak in the system that prevents fuel vapors from escaping, often due to a slightly loose gas cap or a pinhole in a hose.

The Powertrain Control Module (PCM) has detected a very small leak in the Evaporative Emission (EVAP) system.

Common causes

  • Loose, missing, or faulty gas cap

    Even a slightly loose or worn gas cap can cause a very small leak.

    high

    Typical part cost: $0-30 part

  • Small crack or pinhole in an EVAP hose

    Over time, rubber hoses can develop tiny cracks that are hard to spot visually.

    medium

    Typical part cost: $20-100 part

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First things to check

  1. 1Tighten or replace gas cap
  2. 2Visually inspect EVAP hoses for any signs of damage, no matter how small

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Tools you may need

Already have a compatible scanner? Use it. If not, a Bluetooth OBD2 adapter can help you confirm engine codes and check supported live sensor data before replacing parts.

Illustration of a Bluetooth OBD2 adapter, not a product photo

Basic checks

Veepeak OBDCheck BLE

A Bluetooth LE adapter for reading standard engine codes and supported live data.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Regular diagnostics

vgate iCar Pro BLE 4.0

A Bluetooth LE adapter with an automatic sleep feature for routine code and sensor checks.

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Illustration of a Bluetooth OBD2 adapter, not a product photo

Another option

OBDLink CX

A Bluetooth LE adapter to consider when comparing supported vehicles and diagnostic apps.

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Illustrations shown, not product photos. Check vehicle, phone and app compatibility before buying. These adapters do not guarantee access to ABS, airbags or manufacturer-specific systems. Clearing a code does not repair the fault and can reset emissions readiness monitors.

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Related codes

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Frequently asked questions

Is P0456 a serious problem?

P0456 is not usually serious in terms of vehicle operation, but it's an emissions control issue that needs to be fixed to pass inspections and prevent fuel vapor release.

How long can I drive with a P0456 code?

You can typically drive for an extended period without performance issues, but it's recommended to diagnose and fix it within a few weeks to avoid emissions test failures and environmental impact.

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