Mercedes-Benz S-Class Cabriolet 2017 Owner's Manual page 480

Engine
Warning/indicator lamp
;
Engine diagnosis warning
lamp
#
Electrical fault warning
lamp
8
Fuel reserve warning lamp
Possible causes/consequences and
The yellow engine diagnostics warning lamp is lit while the engine is running.
A malfunction has occurred in the engine, the exhaust system or the fuel system.
The emissions limit value may have been exceeded and the engine may be running in emergency operation mode.
Have the vehicle checked as soon as possible at a qualified specialist workshop.
#
The red electrical fault warning lamp is lit.
There is a fault in the electrics.
Observe the messages in the multifunction display.
#
The yellow fuel reserve warning lamp is lit while the engine is running.
The fuel supply has dropped into the reserve range.
Refuel.
#
Display messages and warning/indicator lamps 477
M M Solutions