313 Practical hints
What to do if …
Problem
Possible cause
Suggested solution
?
The yellow “CHECK ENGINE” mal-
function 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 sys-
tem. It allows the accurate identifica-
tion of system malfunctions through 
the readout of diagnostic trouble 
codes. It is located in the front left 
area of the footwell next to the park-
ing brake.
The fuel cap is not closed tightly.
Check the fuel cap.
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.