Information on removing, connecting and changing the battery

Observe SAFETY INSTRUCTIONS FOR HANDLING VEHICLE BATTERY .

Disconnecting the battery

Before disconnecting battery:

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

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

IMPORTANT:

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

General notes on disconnecting 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 versions with an 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 battery is connected.
When installing battery terminal: See TIGHTENING TORQUE .

AGM battery only:

On vehicles with IBS at negative battery terminal:

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.

Connected battery

After connecting battery:

IMPORTANT: 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:

Activate sliding/tilting sunroof, if necessary
Activate power window, if necessary

Refer to the diagnostic system for further vehicle-specific information.

Battery replacement

A vehicle battery is constructed for the installation location and the individual power requirements of the particular vehicle. These individual power requirements depend on the motorization and different types of equipment. The individually assigned vehicle battery is the ideal compromise between the power requirements of the vehicle electrical system and the weight and service life of the vehicle battery.

Vehicles with the automatic engine start-stop function or particular engine types and optional equipment are equipped with a special vehicle battery (AGM battery), since only this battery type can provide elevated power requirements over the extended service life. Installing a different vehicle battery can cause problems with vehicle electronics, can reduce functions or can cause leakage of battery acid.

In the event of an accident where the airbags are deployed in vehicles with a vehicle battery in the trunk, the electrical connection between the vehicle battery and the trigger is automatically disconnected through pyrotechnics. This prevents possible short-circuiting.

Proper operation of all of these safety and convenience functions requires a battery that conforms with specifications and that is properly registered in vehicles with energy management systems (IBS, power module).

Vehicles with energy management systems (IBS, power module): Register battery replacement.

The vehicle electrical system is informed about the vehicle battery characteristic data, such as type, size, age and current power capacity. Therefore, there will always be only one work scope provided that is permitted by the current status of information.

If performance readiness undershoots a defined minimum, a Check Control message will be generated to advise the driver that the battery must be replaced.

When installing a new vehicle battery, the battery must be registered and thus must also be registered with the vehicle electrical system.

NOTE: Only this registration/logon will ensure that the corresponding Check Control message will extinguish again.

Diagnostic system:

Registering the battery replacement:

Service functions
Body
Voltage supply
Register battery change

When retrofitting, a more powerful battery may be used. Standard batteries may always be replaced by AGM batteries with the same specifications.

When installing a battery of a different size or a different battery type, this change in vehicle data must be programmed into the vehicle data in accordance with specifications.

Programming system:

Battery retrofitting