The recall covers certain 2017 through 2020 Audi A4, RS5, A5, S4 and S5 models.
VW says in documents filed with the U.S. safety regulators that a cable in the passenger occupant detection system can be faulty. That can cause software to misdiagnose a malfunction and disable the passenger air bag, increasing the risk of injury in a crash.
Dealers will replace the cable and either the heating mat or the entire seat cover. Owners will be notified by letter starting Jan. 7.
The recall is an expansion of one done for the same problem in 2019. Vehicles repaired in the 2019 recall will have to be fixed again.