Check Engine Code
P0442
Evaporative Emission Control System Leak Detected (Small Leak)
Severity: low
DIY difficulty: 1/5
Typical cost: $0–$300
What P0442 means
The ECM pressurizes the EVAP system and watches for a drop. P0442 = a small leak — the size of a pinhole. This is the classic 'check your gas cap' code: ~30% of the time a cap fix clears it.
Symptoms
- Check engine light
- No drivability issues
Likely causes (most common first)
- Loose or worn gas cap
- Cracked EVAP hose or line
- Failed purge valve or vent valve
- Damaged charcoal canister
- Small crack in the filler neck
Can I keep driving?
Low — mostly emissions/economy
Typical repair cost
DIY fixes can start near $0 (parts only). Shop repairs for P0442 typically run up to $300 depending on the underlying cause and vehicle. Start with the most common cause — Loose or worn gas cap — before throwing parts at it.
Related codes
Confirm P0442 yourself in 60 seconds
AXLY.pro is a free iPhone app that pairs with any Bluetooth OBD2 adapter to read P0442 and every other stored code, plus live engine data. No subscription.