GLK diesel engine uneven idle and fault code

I had a similar issue with my GLK. Uneven idling is a classic symptom of a bad engine mount. Have you checked the condition of the rubber? Look for cracks or excessive wear. Also, give the plug connections a good look. Sometimes it's just a loose or corroded connection causing the problem. Is the vibration really bad, or just a slight tremor?

When you say 'check the condition of the rubber,' do you mean visually inspect it, or is there a more technical way to test for mount wear? And how difficult is it to access the plug connections? I'm not super mechanically inclined, so I'm trying to gauge how much of this I can handle myself.

A visual inspection is a good starting point. Look for obvious signs of damage like cracks, tears, or separation. As for the plug connections, they can be a pain to get to depending on which mount is the culprit. Honestly, if you're not comfortable working on it, I'd recommend taking it to a workshop. 95€ isn't a bad price, and it's better to be safe than sorry.

I decided to take it to a mechanic. Turns out it was a defective engine mount, just like the error code said. They replaced it for the quoted price of 95€. Running smooth now. Appreciate the help!