2005 Mercedes C-Class Owner'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 indicates that the respective systems are operational. They should go out when the engine is running. ! 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 360). Get a jump start ( page 363). 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. i Vehicles with automatic transmission: The SmartKey can only be removed from the starter switch with the gear selector lever in position P. 34