What causes the warning message below in a 2013 BMW 535i?

Hello, BMW's are not "lemons" but all modern vehicles -- especially German engineered vehicles -- have a certain degree of complexity in operation and functionality and will require a trained, experienced BMW technician equipped with proper diagnostic equipment to diagnose and repair it. The concern is likely with an engine performance component or area and will require troubleshooting. German cars that are not still under some kind of warranty are not for the faint of heart financially. Great vehicles, but it's just a fact that diagnostic and repair labor costs come at a premium, as do any needed parts.

Wouldn’t necessarily say all BMW vehicles are lemons.. European vehicles in general seem not to be as reliable in the long run as some of their counterparts - just an option but it has some merit - through the years I have personally witnessed this to be rather factual. Good luck!