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Diagnose/P0456
P0456Low SeverityEmissions

Evaporative Emission System Leak Detected (Very Small)

What This Means

A very small leak has been found in the EVAP system. This is the smallest leak size the system can detect and is often caused by minor seal degradation or tiny cracks in hoses.

Common Symptoms

  • Check engine light on
  • Possible fuel smell
  • No driveability issues
  • Failed emissions test

Common Causes

  • Loose or damaged gas cap
  • Cracked EVAP hose
  • Faulty purge/vent valve
  • Charcoal canister issue
  • Fuel tank pressure sensor failure

Estimated Repair Cost

$50 – $400
Parts and labor (varies by vehicle and location)
Difficulty:Moderate

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For informational purposes only. Diagnostic trouble codes are starting points for diagnosis, not definitive answers. Always consult a certified mechanic for proper diagnosis and repair. Estimated costs vary by vehicle, location, and shop rates.