All codes › P0456
P0456: Evaporative Emission System Leak Detected (Very Small Leak)
What it means
The EVAP test found a very small leak (about 0.020").
Severity: Low Tiny vapor leak; may fail emissions.
Common causes
- Gas cap seal
- Tiny crack in EVAP hose
- Leaking vent or purge valve
- Filler neck seal
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Sometimes DIY. New gas cap first; then a shop smoke test.
Repair cost
SEEDED ESTIMATE Roughly $60–$310
Most likely repair: gas cap. Diagnosis fees, taxes and other causes are not included.
| Line | Low | High | Basis |
|---|---|---|---|
| Gas cap | $14 | $72 | Typical listed retail range, source ($592 outlier excluded) |
| Labor 0.5–1.5 hr | $50 | $240 | $100–$160/hr, shop survey |
⚠️ This is an editorial placeholder range for this type of repair. It is not based on real invoices or licensed pricing data yet. Real ranges will appear here once enough reader invoices for P0456 are verified.
Verified reader invoices for P0456: 0. Share your repair bill to help build real costs.
Tools that can read P0456
- ScanFixAI: Pro $29.99/mo or $249.99/yr
- OBDAI: Annual PRO bundle $299
- BlueDriver Pro Next-Gen: $119.95 list ($99.95 sale seen)
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