All codes › P0455
P0455: Evaporative Emission System Leak Detected (Large Leak)
What it means
The EVAP test found a large leak. Very often the gas cap is missing or loose.
Severity: Low Large EVAP leak, often just the gas cap.
Common causes
- Gas cap missing, loose or wrong
- Disconnected EVAP hose
- Purge valve stuck open
- Cracked canister
Most common causes first. Exact causes vary by make, model and engine.
Can I fix it myself?
Often DIY. Tighten or replace the gas cap, clear the code, and drive a few days.
Repair cost
SEEDED ESTIMATE Roughly $10–$150
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 0–0.5 hr | $0 | $80 | $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 P0455 are verified.
Verified reader invoices for P0455: 0. Share your repair bill to help build real costs.
Tools that can read P0455
- 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)
The Check Engine Weekly
One email a week: new AI diagnostic tools, real repair costs from reader invoices, and one code explained.
Newsletter launching soon.