P0442 Code: EVAP System Leak Detected (Small Leak)
P0442 means the evaporative-emissions system has a small leak that lets fuel vapour escape.
- Applies to
- All OBD-II vehicles (any make or model)
- Est. repair cost
- $20 – $300
- Time to fix
- 1-3 hours
What it means
The most common cause is a loose or faulty fuel cap; also small hose/seal leaks or a faulty purge/vent valve. This is a generic OBD-II powertrain code defined in the SAE J2012 standard, so it applies to virtually any 1996-or-newer OBD-II vehicle — cars, trucks, and modern fuel-injected motorcycles — from any manufacturer (Toyota, Honda, Ford and the rest). Read it with any OBD-II scanner; the meaning is the same across brands, though the exact repair can vary by engine.
Symptoms
- Check engine light on
- Sometimes a faint fuel smell
- No effect on drivability
How to fix it
- 1
Check the fuel cap first
1. Ensure the fuel cap clicks tight; replace a worn cap. 2. If it recurs, smoke-test the EVAP system for small leaks. 3. Clear the code.
Frequently asked questions
Can a loose gas cap cause P0442?
Yes — it’s the classic cause. Tighten or replace the cap first; if the code returns, have the EVAP system smoke-tested.
Last updated July 16, 2026
Guidance only — always consult a qualified professional or the official service manual before carrying out repairs.