Is it a genuine replacement cable for the MS906 with same pinout to scanner end of cable? . Is the OBD 16 pin adapter actually a built in part of the new cable or just transferred connector from the old cable to the new cable? Did you really look close and make sure all 16 pins are still there on the connector and all pins from connector  and have continuity to end of cable ?  Dumb questions but basic sh@t to check look for. Seem to recall Autel had some type of System Update for the MS906 and DS808 in the past that took away the ability of the internal battery to get charged off the vehicle's DLC in an attempt to make the batteries last longer and not sure if it also removed the ability to show DLC voltage afterwards.