P0442: Evaporative Emission Control System Leak (Small)
P0442 is a small leak in the vapor recovery system. It's the most common code triggered by a loose gas cap.
Severity: low · System: Powertrain · Safe to drive: usually, short-term. Not urgent. Try a new gas cap first — it fixes P0442 roughly 30% of the time.
Symptoms
- Check engine light only
- Slight fuel smell (rare)
Common causes
- Loose or bad gas cap
- Small crack in EVAP hose
- Failed purge valve
Fair repair prices
| Tighten / replace gas cap | $0–$40 |
|---|---|
| EVAP purge valve | $100–$250 |
| EVAP hose repair | $100–$300 |
| Smoke test diagnostic | $80–$150 |
Ranges are US market averages (parts and labor). If your shop's quote is above the high end, ask for a line-item breakdown or run it through the invoice checker.
Other codes
- P0300 — Random / Multiple Cylinder Misfire Detected
- P0301 — Cylinder 1 Misfire Detected
- P0420 — Catalyst System Efficiency Below Threshold (Bank 1)
- P0430 — Catalyst System Efficiency Below Threshold (Bank 2)
- P0171 — System Too Lean (Bank 1)
- P0174 — System Too Lean (Bank 2)
- P0455 — Evaporative Emission Control System Leak (Large)
- P0128 — Coolant Temperature Below Thermostat Regulating Temperature