Mercedes ML Overheating Active Air Flap Issue

Sounds familiar. I had a similar issue with my ML, though I can't recall the exact fault code. The check engine light was on and the car overheating was a real concern. I'd check the wiring to the active air flap motor first -- give it a good look for any obvious damage or corrosion. Was the fault code specific about which flap is having issues?

I did a quick visual inspection of the wiring, but did not see anything obvious. Are there any specific tests I can perform to further diagnose the issue before replacing the electromechanism? And regarding the fault code, no, it did not specify which flap was having issues.

If you're not seeing anything visually wrong with the wiring, and the fault code doesn't specify a particular flap, it's likely the motor itself. I chased that for a bit before giving in. Honestly, without more specialized diagnostic tools to pinpoint the exact flap or test the motor, you're probably looking at a trip to a workshop. They can use their diagnostic equipment to properly actuate the flaps and see what's going on. I ended up paying about 590€ for the repair.

I appreciate the information. It confirms my suspicions and helps me to understand the situation better. I will take your advice and schedule an appointment with a trusted workshop to have the issue properly diagnosed and resolved. Thank you again for sharing your experience and the cost you incurred.