Mercedes-Benz CLS-Class 2012 Owners Manual - Manual (Page 250)

Engine
Problem Possible causes/consequences and M Solutions
;
The yellow Check
Engine warning lamp
lights up while the
engine is running. There may be a malfunction, for example:
R in the engine management
R
in the fuel injection system
R
in the exhaust system
R
in the ignition system
R
in the fuel system
The emission limit values may be exceeded and the engine may
be running in emergency mode.
X Have the vehicle checked as soon as possible at a qualified
specialist workshop.
i In some states, you are required by law to immediately visit a
qualified specialist workshop as soon as the yellow Check
Engine warning lamp lights up. If in doubt, check whether such
legal regulations apply in the state/province in which you are
currently driving.
8
The yellow reserve fuel
warning lamp flashes
while the vehicle is in
motion. In addition, the
yellow Check Engine
warning lamp ;
may light up. The fuel system pressure is too low. The fuel filler cap is not closed
correctly or the fuel system is leaking.
X Observe the additional display messages in the multifunction
display.
X Check that the fuel filler cap is correctly closed.
X If the fuel filler cap is not correctly closed: close the fuel filler
cap.
X If the fuel filler cap is closed: visit a qualified specialist
workshop.
8
The yellow reserve fuel
warning lamp lights up
while the engine is
running. The fuel level has dropped into the reserve range.
X Refuel at the nearest gas station.
248
Warning and indicator lamps in the instrument cluster
On-board computer and displays