Mercedes-Benz AG ("MBAG"), the manufacturer of Mercedes-Benz vehicles, has determined that on certain Model Year ("MY") 2012 S-Class (221 platforms) vehicles, the injector codes might no longer be stored in the engine control unit software after installation of the Approved Emission Modification (AEM). The cached injector code may have been lost due to a communication error during installation of the AEM. Customers may experience the MIL illumination or in rare cases, increased engine noise or rough running.
MBUSA will conduct an Emission Service Campaign in which an authorized Mercedes-Benz dealer will recode the correct injector codes to the engine control unit on the affected vehicles
