Every 15,000 km.
It is necessary to place the car on supports and remove the front wheels.
The thickness of the brake pads can be checked through the hole on the front side of the caliper.
To more accurately check the thickness of the brake linings, they must be removed and cleaned.
If the thickness of any of the brake linings has decreased more than the permissible value, replace all four brake linings on both wheels.
[The original article is located on the online resource «audimanual»]