I have a 2015 450L too, hi bought it used and the gauge doesn’t work. The PO said it failed after 3 months. But, the fuel gauge and other displays work. No RPM or MPG. When you start it it gives a long RRRRRRRRRRR might be a 60 at the end, not sure. But then it just goes blank. I am going to try resetting some connections to see if that helps but I’m afraid the gauge is shot. $300.