GF82.85-P-2006SKB Switch On/Off Behavior, Function

GF82.85-P-2006SKB Switch On/Off Behavior, Function
- with CODE (523) MB Audio 20 radio

Activating the overall system
Position 0 (key in lock)
In order to ensure a quicker switch-on process, only the bus systems are activated for t = 3 min by inserting the transmitter key (A8/1) in the electronic ignition switch control unit (N73), position 0 (circuit 15C). If the radio (A2) is switched on with the "ON" button (On/Off), it is switched off automatically after t = 30 min.

Position 1 (radio setting)
The unit is switched on by turning the transmitter key (A8/1) into position 1 (circuit 15R ON), provided it was switched on before the last time the transmitter key (A8/1) was removed. It remains in operation until the transmitter key (A8/1) is removed again.

The function options are limited to:
^ Operating the radio (A2)
^ Multifunction display on top (A1p13) in instrument cluster (A1)
^ Operation via multifunction steering wheel

Position 2 (ignition)
By turning the key further to position 2 (circuit 15 ON) all functions in the vehicle are rendered operational. The system which was active before it was last switched off (e.g. radio (A2)) is switched on and the corresponding basic menu is displayed.
If the radio (A2) has been switched off for longer than t = 30 min, a warning menu appears with general instructions for using the system.

Position 3 (motor start)
In position 3 (Circuit 50 ON) the engine is started. If a considerable voltage drop occurs while the engine is being started, the system switches itself off during the time of the motor start, and is switched on again after the on-board electrical system has stabilized.

Conduct for operating the ON/OFF button
The radio (A2) can also be switched on during "circuit 15C OFF" by pressing the ON button (ON/OFF) at the combination push and rotary switch. All Media Oriented System Transport (Most) functions will then be available for t = 30 min. The system switches of automatically once this time has elapsed.

On/Off characteristics via AUTO-ON
If a telephone call or an SMS is received, the telecommunications control unit (N112) or the UPCI (Universal Portable CTEL Interface) control unit (N123/1) is activated during the run-on time and initiates a wake-up pulse via the MOST.

The system components are then "woken up", the MOST system is operational in order to provide the required functions. If the system has switched off after 30 minutes, the system can be switched on again by pressing the ON button. The cycle of 30 minutes then starts from the beginning.
The system is either switched off via the ON button (ON/OFF) or with "circuit 15C OFF". An active phone call is not interrupted by removing the transmitter key (A8/1). In this case, the MOST system switches itself off.

Switch off characteristics
The radio (A2) is switched off with "circuit 15C OFF". It is always in "standby mode", if the Controller Area Network bus class B (interior) (CAN-B) is active.

Switch off characteristics at undervoltage
The control electronics of the radio (A2) constantly monitor the battery voltage. Depending on the voltage value the system will act as follows:
If the battery voltage drops below 11.5 V (battery warning range), a message appears in the display and requests that the engine be started. If the engine is not started, a further warning follows after 3 minutes that approx. 10 seconds remain for starting the engine before the device switches off. In this case switching on the engine prevents the system from being automatically shut down. If the system has shut down and the voltage reading rises again above 11.5 V, the radio (A2) will not be automatically activated.

If a system has been shut down, it can be switched back on again manually. However, the warning procedure ensues each time until the fault is eliminated.

Battery voltage below 9.5 V (undervoltage)
The radio (A2) is automatically put in a defined standby condition, in which only the battery voltage is monitored.
In addition to this the current operating status is stored. In this condition the radio (A2) cannot be operated or made to respond via the DIAGNOSIS. Communication with external components does not take place.