DTC C1649-08: CAN Time-Out EMS For ACC/SCC: General Description
WARNING: This page is about a different car, the 2021 Kia Seltos. However, it is still accessible from the selected car via links, so may be relevant.
The Hydraulic Electronic Control Unit (HECU) sends requirement data, such as torque reduction, the number of fuel cut cylinders, and the ESC control request, to the ECM through CAN bus line. The ECM performs the fuel cut function according to a request signal from the HECU and then retards an ignition timing. The Transmission Control Module (TCM) maintains current gear position during the ESC control period in order not to increase power which causes a kickdown shift.