V40 Control Unit Communication Error

Whoa, sounds familiar! I had something like that happen in my V40. Check engine light, coolant all over the place... It was a total mess. You mentioned a control unit error? What diagnostic trouble code did you pull? Could be a software glitch too, but definitely start with the obvious stuff like checking the connections.

The diagnostic trouble code points towards a communication fault within the engine control unit network. When you experienced this issue, did the diagnostic trouble code also indicate a communication error? Where exactly was the issue, so I can check it myself?

Yep, pretty sure it was a communication error code. I fiddled with some stuff but honestly, I'm not the best with engines. I ended up taking it to a workshop. They found a corroded connection somewhere near the ECU. Worth checking all the connections before you spend too much though! Good luck!

Your shared experience proved invaluable. After meticulously inspecting the cable connections, I found that the error was indeed caused by a defective plug connection. A replacement part cost me a mere 95€! Thank you for pointing me in the right direction!