199 Practical hints
What 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 sys-
tem. It allows the accurate identifica-
tion of system malfunctions through 
the readout of diagnostic trouble 
codes. It is located in the passenger 
compartment near the engine hood 
release.
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.
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The red seat belt warning lamp 
blinks for a brief period after 
starting the engine.
The warning lamp reminds you to fasten seat 
belts.
Fasten your seat belt.