BERLIN — Volkswagen says its management has informed its board about “the current situation regarding possible cartel law issues” following a report that Germany’s biggest car makers colluded for years over diesel technology and other issues.

German weekly Der Spiegel reported Friday that employees of Volkswagen, Audi, BMW, Mercedes and Porsche had met often since the 1990s and had agreed to limit the size of the tanks holding a urea solution used to reduce diesel emissions of harmful nitrogen oxide.

Volkswagen said Wednesday it “has no comment to make at the present time on details of these issues or on speculation.” However, it added that “as a general principle, Volkswagen works very closely with the authorities in a spirit of cooperation and trust.”