Audi has announced a recall involving around 530,000 mild-hybrid A4, A5, A6, A7, and Q5 models worldwide. Moisture can penetrate the BSG (Belt-Starter-Generator), which can lead to a short circuit and overheating of the generator. Subsequent fire in the engine compartment is not excluded.
According to KBA (German Federal Motor Transport Authority), 53,250 cars out of a total of approximately 530,000 are registered in Germany. Models A4, A5, A6, A7, and Q5 with the production period between May 2017 to March 2020 are affected. Both the European Rapex system and the US National Highway Traffic Safety Administration (NHTSA) state that the vehicles are equipped with a mild-hybrid system and a two-liter TFSI petrol engine (EA888).
The recall code is “27H2” and the generator should be replaced in an authorized workshop. Audi states that no property damage or injuries are yet known in connection with this defect.
What is the BSG (Belt-Starter-Generator)
The system replaces a conventional starter pinion and is driven by a belt connected to the engine crankshaft. Together with a lithium-ion battery, the belt-starter generator forms the heart of the mild-hybrid (MHEV) system. When the driver applies the brakes during everyday driving, the system converts a large percentage of the braking energy – normally lost in the form of heat – into electrical energy for future use.