Mercedes-Benz 2009 C-Class Operator's Manual page 314

Practical hints
Vehicle status messages in the multifunction display
Display messages
G Warning!
If the 5/ indicator lamp remains
illuminated with an adult occupant on the
312
Possible cause/consequence
front passenger seat even after performing
the above corrective steps, do not have any
Possible solution
necessary check cycles and to make sure
neither message appears in the multifunction
display.
If above conditions are met, you can occupy the
passenger seat again. Depending on the
passenger classification sensed by the OCS, the
5/ indicator lamp will remain illuminated
or go out.
If above conditions are not met, the system is not
working properly. Have the system checked as
soon as possible at an authorized Mercedes-Benz
Center.
passenger use the front passenger seat
until the system has been repaired.