General notesGeneral notes  - Battery - Checking and topping up fluids - General maintenance - Audi A4 Owner's Manual - Audi A4

All work on batteries requires specialist knowledge.

The battery is virtually maintenance-free. It is checked as part of the Inspection Service.

We recommend that you replace a battery once it is older than 5 years.

When an airbag is triggered, the battery will, under certain circumstances, be disconnected from the on-board power supply for safety reasons ⇒ on page 201. in General notes on airbag system on page 201.

Disconnecting the battery

If the battery is disconnected, some of the vehicle's functions will become inoperative (e.g. electric windows). These functions will require resetting after the battery is reconnected. For this reason, the battery should only be disconnected from the vehicle's electrical system when absolutely necessary.

If the vehicle is not used for long periods

If you do not drive your vehicle for a period of several days or weeks, the power management will gradually shut off the on-board systems one by one, or reduce the amount of current they are using. This limits the amount of power consumed and helps to ensure reliable starting even after a long period.

Please note that certain convenience features, such as the Audi advanced key*, the remote control key or the electrical seat adjustment may not be available when you unlock the vehicle. These functions will be restored when you switch on the ignition and start the engine.

Winter conditions

At low temperatures the battery has to work very hard. It also provides only a fraction of the starting power it has at normal temperatures.

For this reason, we recommend having the battery checked and charged if necessary before the start of winter.


  • All work on batteries requires specialist knowledge. For queries regarding the vehicle battery please contact an Audi dealership or other qualified workshop (risk of chemical burns / risk of explosion).
  • The battery must not be opened. Do not attempt to make any changes to the electrolyte level of the battery. Otherwise, there is a risk that a mixture of oxygen and hydrogen gas can accumulate and cause an explosion.

If the vehicle is to be left standing for a period of several weeks at extremely Note

If the vehicle is to be left standing for a period of several weeks at extremely low temperatures, the battery should be removed from the vehicle. This ensures that it cannot freeze up and be damaged.