Audi is releasing a software calibration update to the Approved Emissions Modification (AEM). This software calibration will include the following changes to the vehicles emissions control and on-board diagnostics (OBD) software: (1) It will correct an issue that is causing the 'check engine' light to falsely illuminate under certain driving conditions, which has resulted in replacement of the diesel oxidation catalyst (DOC) for certain customers; (2) It will reduce the likelihood of experiencing an engine shudder that could occur during certain warm-up driving conditions; and (3) It will improve OBD monitoring of vehicle emissions systems and otherwise improve the software used by your vehicle.