Contact Corrosion
WARNING: This page is about a different car, the 2014 Volkswagen Touareg, 2013 Volkswagen Touareg, 2012 Volkswagen Touareg, and 2011 Volkswagen Touareg. However, it is still accessible from the selected car via links, so may be relevant.
Contact corrosion can occur if incorrect fasteners (bolts, nuts, washers, etc.) are used.
For this reason, only fasteners with a special surface coating are installed.
In addition, rubber or plastic parts and adhesive are made of materials that do not conduct electricity.
If there are doubts about whether parts can be used or not, then use new parts. Refer to the Parts Catalog.