On/Off Behavior, Function

Switch-on behavior
Activation of navigation
When the driver's door is opened the navigation feature is automatically activated via CAN bus (A1-A40/3). This procedure requires approx. 2 s and may be accompanied by weak audible noises from the CD-ROM drive integrated into the navigation processor. The display on the COMAND operating, display arid control module (A40/3) remains switched off.

When the status of the ignition switch then does not change (e.g. circuit 15C or 15R ON) the navigation feature remains activated for 30 minutes.

Activation of entire system
When the ignition switch is turned to the approx. 20 ° position (c. 15C ON) all other subsystems are activated, in position 1 (c. 15R ON) the display is switched on if the COMAND module was switched on before the ignition key was removed previously. The COMAND system is then ready for operation. The system active before it was last switched off (e.g. radio) is switched on and the corresponding basic menu displayed. If the COMAND feature was switched off for longer than 30 minutes, a warning menu appears with general information on the use of the system.

Effect of pressing "ON" button
COMAND can also be switched on by pressing the "ON" button even when the remote control key (A8/1) is not inserted. All COMAND functions are then available for 30 minutes. After expiration of 30 minutes, the COMAND system automatically switches off.

The system can be switched on again by pressing the "ON" button, when it has switched off after 30 minutes. The 30 minutes cycle then starts again from the beginning.

Switch-off behavior
The COMAND system is switched off when the ignition key is removed (C. 15C OFF). The 30 minutes shut-off delay ("stand-by operation") for the navigation system then starts. During this time, all important location finding parameters remain stored.

Moreover, the COMAND operating, display and control module (A40/3) is always in "stand-by operation" when the CAN passenger compartment bus is active.

NOTE: Pressing the "Monitor" button, only changes over between day, night and off mode for the monitor.

Switch-off characteristics when voltage is too low
The COMAND central processor continuously monitors the battery voltage. The system behaves as follows depending on the voltage value:

- Battery voltage 11.5 to 9.5 V (battery warning range)
If the battery voltage drops to below 11.5 V, a message appears on the display requesting the driver to start the engine.

If the engine is not started, another warning is given after 3 minutes indicating that 10 s still remain to start the engine before the system switches off. In this case, starting the engine prevents the system from switching off automatically. If the system has switched off and the voltage again increases to above 11.5 V, the COMAND system does not switch back on automatically.

After switching off, the system can still be switched on manually. The warning procedure is then started again each time for as long as the problem is not eliminated.

- Battery voltage less than 9.5 V (voltage too low)
The COMAND system is automatically switched to a defined stand-by status in which it only continues to monitor the battery voltage. In addition, the current operating state is stored. In this state, the COMAND system cannot be operated or actuated via Star Diagnosis. Communication with external components is no longer accomplished.