TECHNICAL SERVICE BULLETIN: SERVICE ACTION: IVT SOFTWARE LOGIC IMPROVEMENT AND/OR IVT REPLACEMENT (SA424) - This bulletin has been revised to include additional information. New/revised sections of this bulletin are indicated by a black bar in the margin area. This bulletin provides the procedure to improve the Transmission Control Module (TCM) logic and if necessary, replace the Intelligent Variable Transmission (IVT) on 2019-2021MY vehicleswhich may exhibit a MIL with certain DTC(s).