alexanderraven78

CLA fuel tank ventilation issue

My 2018 Mercedes CLA with a gasoline engine is throwing me for a loop. Check engine light is on, and the engine sometimes stalls at idle. Seems linked to a fuel tank ventilation system leak. I'm suspecting the activated charcoal filter, but has anyone else run into this? I'm getting worried about fuel efficiency. Could the purge valve also be involved?

4 comment(s)

Have you inspected the EVAP system? I experienced similar difficulties with my CLA; a defective purge valve could be the culprit. It might be prudent to perform a leak detection test to verify the source of the leak.

Leak detection test... interesting. Is that something a regular OBD2 scanner can handle, or are we talking specialized equipment?

A standard OBD2 scanner might display a code related to the EVAP system; however, pinpointing the exact location of the leak could need specialized equipment. Given the symptoms and your suspicion of the charcoal filter, visiting a workshop for a thorough diagnosis may be the most effective course of action.

Thanks for confirming my suspicions. Took it to a trusted mechanic; leak detection pointed directly to the charcoal filter. Replaced it, and the check engine light is gone, and idle is smooth again. Total cost came to 275€ Appreciate the advice.

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