Eseries Overheating Check Engine Light

I also own an Eseries diesel, and your issue sounds familiar. Overheating and the check engine light were my first signs too. Did you notice rough idling or unusual fuel consumption before the overheating?

Yes, now that you mention it, the engine has been idling rougher, and I've been going to the gas station more often. What did you have to do to fix it?

It turned out to be a defective cable/plug connection causing communication issues and weird sensor readings. I spent time tracing the fault but had to take it to a workshop. They sorted it quickly. I recommend a mechanic, as they probably have better diagnostics tools.

Thanks for the advice! You were spot on. The Eseries had a faulty plug connection causing the control unit communication error. They replaced the cable, and everything seems normal. The repair cost 95€. Hopefully, this will assist anyone else that encounters it too.