Do not add anything to the oil. The recommended oils meeting the dexos specification are all that is needed for good performance and engine protection.
Engine oil system flushes are not recommended and could cause engine damage not covered by the vehicle warranty.
Selecting the Right Engine Oil
(Diesel Engines)
What to Do with Used OilEngine Control Module Description Engine Control Engine Control Module
The Engine Control Module (ECM) interacts with many emission related components andsystems, and monitors emission related components and systems for deterioration. OBDII diagnostics monitor the system performance and a diagnostic trouble code (DTC)sets if the system performance degrades. The ECM is ...