294 Practical hintsWhat to do if …?Problem
Possible cause
Suggested solution
?(USA only)±(Canada only)
The yellow malfunction 
indicator lamp comes on 
while driving.
There is a malfunction in:
The fuel management system
The ignition system
The emission control system
Systems which affect emissions
Such malfunctions may result in excessive 
emissions values and may switch the en-
gine to its limp-home (emergency opera-
tion) mode.
Have the vehicle checked as soon as 
possible by an authorized 
Mercedes-Benz Center.
An on-board diagnostic connector is 
used by the service station to link the 
vehicle to the shop diagnostics system. 
It allows the accurate identification of 
system malfunctions through the read-
out of diagnostic trouble codes. It is lo-
cated in the front left area of the 
footwell next to the parking brake pedal.
The fuel cap is not closed tightly.
 Check the fuel cap (
page 257).
Your gas tank is empty.
After refuelling start the engine three or 
four times in succession. 
The limp-home mode is canceled. You do 
not need to have your vehicle checked.
l
The red Distronic warn-
ing lamp comes on while 
driving.
You are too close to the vehicle in front of 
you to maintain selected speed.
Apply the brakes immediately to in-
crease the following distance.