P0442 Subaru Forester
EVAP System Leak Detected (Small Leak) · Powertrain Code · Low · Repair: Easy
What is P0442?
A small leak has been detected in the EVAP system. Common causes include a loose or cracked gas cap, cracked EVAP hose, or faulty purge/vent valve.
When the Subaru Forester triggers code P0442 (evap system leak detected (small leak)), it typically points to an issue in the powertrain system. Below you'll find the most common causes, symptoms, and repair options specific to the Subaru Forester.
This repair is rated easy, meaning basic tools, no lift needed.
Diagnostic data on this page is compiled from publicly available repair resources and technical service bulletins. Always have a qualified mechanic confirm the diagnosis before authorizing repairs on your Subaru Forester.
Common Causes on Subaru Forester
- Gas cap seal failure due to worn O-ring
- EVAP purge valve not sealing completely
- Small crack in EVAP vapor line near charcoal canister
- Fuel filler neck seal corrosion in rust belt climates
- Charcoal canister deterioration from moisture exposure
Symptoms
- Check engine light illuminated
- Faint fuel smell near vehicle
- Slightly reduced fuel economy
- Failed emissions test
- Occasional rough idle after refueling
Notes for Subaru Forester
Subaru gas cap seal and purge valve failures are the most common P0442 causes on Outback, Forester, Crosstrek, Impreza, and Ascent.