P0442Powertrain
Powertrain · SAE
EVAP System Leak Detected (Small Leak)
Meaning
The ECU has detected a small leak in the evaporative emissions system. The EVAP circuit is not fully sealed, but the leak is minor in size.
Common causes
- Loose fuel cap or cracked cap seal
- Small crack in an EVAP hose
- Leaking purge or vent valve seal
- Slightly loose canister connection
- Hairline crack in the filler neck
Symptoms
- Check-engine light on
- Occasional fuel smell
- Possible emissions-test failure
- No noticeable effect on drivability
- Light that may come and go between fill-ups
Severity
Moderate: a small emissions leak with no immediate mechanical risk.
What to do
- Check and properly retighten the fuel cap, inspecting its seal
- Inspect the EVAP hoses for hairline cracks or loose connections
- Run a leak test (smoke or pressure) to pinpoint the leak
- Check the seal of the purge and vent valves