276 Practical hintsWhat to do if …Problem
Possible cause
Suggested solution
?
The yellow “CHECK ENGINE” 
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 engine 
to its limp-home (emergency operation) 
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 identifi-
cation of system malfunctions 
through the readout of diagnostic 
trouble codes. It is located in the front 
left area of the footwell next to the 
parking brake pedal.
The fuel cap is not closed tight.
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.