Certain 20MY Elantra (AD/ADa) vehicles may experience an illuminated check engine warning light due to Diagnostic Trouble Codes (DTC) listed below. Perform the Transmission Control Unit (TCU) update, and, if necessary, replace the IVT (Intelligent Variable Transmission) to resolve this condition. This update also includes the software for optimizing CLR_DIST (distance traveled since DTCs cleared) display.