Turbo Lost its Nut?
This bulletin applies to 2012 Audi A3 equipped with a 2.0L turbocharged engine. Complaints may include poor acceleration response, rough gear changes, turbo lag and slightly delayed power transmission.
The pulling away clutch of the DSG closes when the brakes are released and is therefore under load. The delayed power transmission is caused by a late and rapid boost pressure build-up.
Perform a visual check of the turbocharger. Make sure that the stud with clamp nut is on the turbocharger. If the stud or clamp nut is missing, replace the turbocharger. Attempt to find the missing nut. It is often lying on the engine undertray assembly. A replacement turbocharger is available as P/N 03L253056.