VOLUNTARY EMISSIONS SERVICE CAMPAIGN: THETA 2.0L T-GDI ECM SOFTWARE LOGIC IMPROVEMENT (SC279) - This bulletin provides information to upgrade the software logic of the engine control module (ECM) with an improved version on 2018-2021MY Stinger (CK) vehicles equipped with a Theta 2.0L T-GDI ULEV engine manufactured from September 29, 2017 through January 20, 2021. The subject vehicles may have engine calibrations that were not optimized for emissions standards under certain specific conditions, which may cause the vehicle to release air pollutants which exceed Federal and California standards (such as NMOG (Non-Methane Organic Gas) and CO (Carbon Monoxide) during IUVP (In-Use Verification Program). To ensure compliance with emissions regulations, apply the improved logic to the âÂÂENGINEâ system using the KDS ECU Upgrade function as described in this bulletin.