Mokka Fuel Tank Ventilation Leak

A fuel tank ventilation system leak seems likely given the symptoms. The activated charcoal filter is a common failure point. Have you checked the purge valve or pressure sensor? A faulty purge valve can cause incorrect airflow. How did you check for leaks?

I used a smoke tester and saw smoke near the charcoal canister. I've only visually checked the purge valve and pressure sensor. How can I properly assess these components?

Smoke near the charcoal canister strongly suggests it's compromised. A faulty purge valve or pressure sensor could contribute, but the smoke test is indicative. Given the Mokka's age and mileage, a degraded charcoal filter is plausible. Get a workshop to inspect it thoroughly. Sounds like a 275€ repair.

I took the Mokka to a local workshop. They confirmed the activated charcoal filter was defective and the source of the leak. Replacing it fixed the issue and the check engine light is now off. Thanks for the help!