I mean RED red. Not the standard orange hue that all BMW gauges and displays are.
Every time you start your car, it flashes a service display for 5 seconds. That tells you how many KMs you can drive to your next oil change, or if you need a service of any kind, it will display service in bright red. If you still can't figure it out drive to any BMW dealership and bring your key to a service advisor, the key will tell him what your car needs.