I have a yellow triangle with an exclamation mark

The yellow exclamation point close to the center of the odometer looks like an exclamation point surrounded by parentheses. This light means you should check your tire pressure. Once you have checked the air in the tires and remedied any issues, push the "Set" button on the dashboard. The light should disappear.

time for a service. or oil to low. time to top up.

if its appearing on the lhs off the dash its just when your tyres are losing grip whith the road surface.

Hi, The exclamation point in triangle blinking is the "Emergency Blinker" This blinker turns on all all of the turn signal lamps at all four corners of the car. Left and Right, Front and Back. The triangle represents the European symbol for roadside emergencies. In fact on European Mercedes and other cars there is a triangle shaped reflector you can put behind the car so that other drivers know you have an emergency. THAT TRIANGLE ON YOUR DASHBOARD IS A BUTTON. PUSH IT ONCE. THE BLINKING SHOULD STOP. If you have a roadside emergency, and are broken down by the side of the rode. Push the Red Triangle and your lights will blink on and off ouTside to say, in effect "help".
Hope this helps.
Best,
Mark

If it looks like a deflating tire with an exclamation mark inside, its the check your tire pressure light.

If its a triangle with exclamation mark inside its the check engine light.

dealer only ,ABS -- encrypted software so you cannot read the fault

you have a brake fault

It is the Tire Pressure Mounted System (TPMS). It monitors the air pressure in your tires. If it is on, you have low tire pressure...or like me, it's just a faulty indicator. Mine came on, but I don't even have TPMS on my vehicle.