Notes for disconnecting and connecting the vehicle battery

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 stored in some control units.

Attention!

There is a danger of mixing up battery cables: If the positive and negative battery cables are of the same color, trace the polarity up to the vehicle battery in case of doubt, then mark and cover the cables
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.
If necessary deactivate installed auxiliary batteries as per vehicle-specific repair instructions and disconnect if necessary. Cover battery negative terminal(s) and secure.
Disconnect terminal of negative battery cable from 12 V on-board electrical system/vehicle battery only after successful and confirmed deactivation of any installed intelligent additional batteries. Cover battery negative terminal(s) and secure.
Disconnect both negative battery cables in version with non-intelligent auxiliary battery. Cover battery negative terminal(s) and secure.
When working 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:
On vehicles with IBS at negative battery terminal:
Do not under any circumstances detach/lever off terminal covers by force.

Never loosen the hexagon socket bolt of the IBS!

Note the following after having connected the vehicle battery:

Attention!

After an open circuit, some systems may be restricted in their use.

Personal Profiles may also be lost.

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

For example:
Activate sliding/tilting sunroof, if necessary
Activate power window, if necessary
Refer to the diagnostic system for further vehicle-specific information.