— Mercedes-Benz is recalling more than 670 cars to fix problems with seat belts that may fail to protect an occupant in a crash.
Mercedes says the recalled cars include the 2016-2017 S63 AMG Coupe, S65 AMG Coupe, S550 Coupe 4Matic, S63 AMG 4Matic Convertible and the S550 Convertible.
In February 2016, Mercedes opened an internal investigation after reports of seat belt extenders that weren't retracted in the cars. Engineers say the control units were not properly coded to account for the friction conditions during activation of the seat belt extenders.
The automaker says an occupant can be injured from a combination of the seatbelt slack resulting from an extended seatbelt, or possibly injured from a broken extender during a crash.
The recalled 2016-2017 Mercedes-Benz S63 AMG Coupe, S65 AMG Coupe, S550 Coupe 4Matic, S63 AMG 4Matic Convertible and S550 Convertible cars were built from June 29, 2015, to March 15, 2016.
The recall will begin in December 2016 when dealers will start updating the control unit software.
Affected owners with questions may call Mercedes-Benz at 800-367-6372.
CarComplaints.com has complaints about numerous models of Mercedes-Benz cars.