P0442 GMC Terrain
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 GMC Terrain 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 GMC Terrain.
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 GMC Terrain.
Common Causes on GMC Terrain
- Worn or cracked gas cap O-ring
- EVAP purge solenoid stuck partially open
- Small crack in EVAP vapor hose near charcoal canister
- Fuel filler neck seal deterioration
- Charcoal canister vent valve not sealing properly
Symptoms
- Check engine light illuminated
- Faint fuel smell near vehicle
- Slightly reduced fuel economy
- Failed emissions test
- Occasional rough idle after refueling
Notes for GMC Terrain
On Equinox and Terrain, always check the EVAP purge solenoid first as it is the most common cause of small leak codes on these platforms.