P0456 Evaporative Emission Control System Leak Detected (Very Small Leak)
What does P0456 mean?
P0456 — Evaporative Emission Control System Leak Detected (Very Small Leak). This is an OBD-II diagnostic trouble code a scanner retrieves when your vehicle's computer detects evaporative emission control system leak detected (very small leak). The level of risk depends on how the vehicle is currently running and how long you've been driving with the light on.
Common causes of P0456
- Cracked or aged fuel cap gasket
- Pin-size holes in EVAP hoses
- Leaking O-rings at the fuel tank or pump assembly
- Faulty purge or vent valve sealing
- Cracked charcoal canister
How to fix P0456
- Inspect and replace the fuel cap gasket if damaged
- Perform an EVAP smoke test with a very sensitive smoke machine
- Check EVAP lines and connectors for hairline cracks
- Test purge and vent valves for proper sealing
- Replace any leaking components identified by the smoke test