Check Engine Code
P0456
Evaporative Emission Control System Leak Detected (Very Small Leak)
Severity: low
DIY difficulty: 2/5
Typical cost: $0–$300
What P0456 means
Pinhole-level leak in the EVAP system. Hardest to find because the leak is so tiny.
Symptoms
- Check engine light only
Likely causes (most common first)
- Slightly loose or failing gas cap seal
- Hairline crack in an EVAP hose or grommet
- Failing purge valve
Can I keep driving?
Low — mostly emissions/economy
Typical repair cost
DIY fixes can start near $0 (parts only). Shop repairs for P0456 typically run up to $300 depending on the underlying cause and vehicle. Start with the most common cause — Slightly loose or failing gas cap seal — before throwing parts at it.
Symptoms that match P0456
If you got here from a search query, one of these might describe what your car is actually doing:
Related codes
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