Notes for disconnecting and connecting the vehicle battery (M3 base, M3 Competition, M3 Competition M xDrive, M3 CS)

Observe SAFETY INSTRUCTIONS for handling vehicle battery.

Before disconnecting vehicle battery:

Turn off the ignition and other electrical loads/consumers to prevent spark formation when reconnecting

NOTE: If the ignition is not switched off when the vehicle battery is disconnected, fault memories may be set in some control units

Attention!

There is a danger of mixing up battery cables: if the positive battery cable and battery ground lead are the same color and you are in doubt, follow the polarity to the vehicle battery, then mark and cover the leads
The on-board computer and clock may lose your data

General notes on disconnecting the vehicle battery:

Do not disconnect battery leads and leads from alternator and starter motor while engine is running
Disconnect terminal of battery ground lead from the battery. Cover battery negative terminal(s) and secure
Disconnect both battery ground leads in version with auxiliary battery. Cover battery negative terminal(s) and secure
When work is carried out on the electrical system, faults may be caused in the fault memories of some control units when the vehicle battery is connected

Only lead AGM battery:

Do not under any circumstances detach/lever off terminal covers by force

Do not under any circumstances release the hexagon socket screw of the IBS

Note the following after having connected the vehicle battery:

Attention!

The scope of application of some systems may be restricted after an open circuit

Personal Profiles may also be lost

Settings or activations must be carried out, depending on the equipment specification

For example:

Refer to the diagnostic system for further vehicle-specific information