Actuator frames in UDS protocols over CAN Bus are messages used by automotive scanners to control electronic vehicle functions such as mirror folding, lights, door locks, and windows. During the reverse engineering process performed on a Hyundai Ioniq 5, the main focus was on service 0x2F (InputOutputControlByIdentifier), used to activate actuators, and service 0x22 (ReadDataByIdentifier), used to read system states and live data signals. For example, when the scanner sends an actuator request such as 2F F0 10 02, the ECU must respond with a positive frame like 6F F0 10 02, indicating that the requested function was accepted correctly. In many cases, these responses must follow ISO-TP multi-frame structure, including proper Flow Control handling and extended diagnostic sessions such as 10 03; otherwise, the scanner will not enable the actuator functions. Additionally, signals such as “Out Side Mirror Auto Folding Status”, “Mirror Fold Output”, and “Mirror Unfold Output” were analyzed to understand both the logical mirror status and the real motor activation outputs. Throughout this work, the CAN Bus Multiplex Trainer was an essential tool for reverse engineering because it allowed ECU simulation, custom UDS frame responses, and real-time monitoring of the ThinkDiag scanner behavior, greatly improving the understanding of how CAN and UDS actuator frames should be interpreted and correctly answered in the Hyundai Ioniq 5.
