Battery Disconnecting Procedure on Vehicles with MK3 Nav System
MODEL E38, E39 with Nav from 09/00
E52, E53 with Nav from 10/00
E46 with Nav from 06/00
SITUATION The MK3 Navigation computer powers down in approximately 60 seconds after the ignition has been turned OFF (red LED on the
computer goes OFF).
If the power supply to the MK3/4 unit is interrupted (by removing/disconnecting the computer from the vehicle, or by disconnecting the
vehicle's battery) in the time period of 55 to 57 seconds after the ignition has been turned OFF, the power-down procedure ("erase
and save data in Non Volatile RAM") can be corrupted. This will result in a total failure of the MK3/4 computer (red LED off, CD eject
function inoperative, board monitor screen permanently blank, and no sound from the audio system). In such a case, the navigation
computer has to be replaced.
CORRECTION On vehicles with MK3 navigation system, prior to disconnecting the battery or removing (disconnecting) the Nav computer, make
sure the MK3 Nav computer is in the power-down mode (red LED on the unit is OFF).
MODEL E38, E39 with Nav from 09/00
E52, E53 with Nav from 10/00
E46 with Nav from 06/00
SITUATION The MK3 Navigation computer powers down in approximately 60 seconds after the ignition has been turned OFF (red LED on the
computer goes OFF).
If the power supply to the MK3/4 unit is interrupted (by removing/disconnecting the computer from the vehicle, or by disconnecting the
vehicle's battery) in the time period of 55 to 57 seconds after the ignition has been turned OFF, the power-down procedure ("erase
and save data in Non Volatile RAM") can be corrupted. This will result in a total failure of the MK3/4 computer (red LED off, CD eject
function inoperative, board monitor screen permanently blank, and no sound from the audio system). In such a case, the navigation
computer has to be replaced.
CORRECTION On vehicles with MK3 navigation system, prior to disconnecting the battery or removing (disconnecting) the Nav computer, make
sure the MK3 Nav computer is in the power-down mode (red LED on the unit is OFF).
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