Mercedes-Benz 2005 C 240 Operator's Manual page 36

Getting started
Unlocking
i
When you switch on the ignition, the
indicator and warning lamps in the
instrument cluster come on. This indi-
cates that the respective systems are
operational. They should go out when
the engine is running.
i
The SmartKey can only be removed
from the starter switch with the gear
selector lever in position P.
34
!
If the SmartKey cannot be turned in the
starter switch, the battery may not be
sufficiently charged.
Check the battery and charge it if
necessary ( page 347)
Get a jump start ( page 350).
To prevent accelerated battery
discharge and a possible dead battery,
always remove the SmartKey from the
starter switch when the engine is not in
operation.