Grandeur BUS System Error

The symptoms you describe suggest a potential communication issue within the vehicle's BUS system. I encountered similar problems with a 2014 Volvo XC60. To confirm, did the scan tool provide any specific error codes? Also, have you noticed any patterns regarding when these errors occur (e.g., during specific weather conditions or after driving for a certain duration)?

Thanks for the reply! The scan tool showed a generic 'System Failure' error, nothing specific, which is why I'm so lost. Regarding patterns, it seems pretty random. Sometimes it happens on short trips, other times on long drives. Weather doesn't seem to matter either. What was the issue with your Volvo, and how did you fix it?

In my Volvo's case, the root cause was a defective cable connection to one of the control units, specifically its connection to the BUS system. This resulted in intermittent communication errors, mirroring your symptoms. Given your Hyundai's age and mileage, a similar issue is plausible. I recommend a thorough inspection of the wiring harness and connectors associated with the central control unit. If you're not comfortable doing this yourself, a qualified technician can diagnose the issue more precisely. It's probably a visit to the workshop.

Thanks so much for the advice! Based on what you said, I took it to a local mechanic and they found a loose connection on the BUS system cable, just like you guessed. They fixed it for about 155€. Everything seems to be working fine now. Really appreciate your help!