Can someone please help me understanding this. Generally J1939 is the standard in trucks so they mostly follow the 29 bit identifiers. But if you come to cars they do not follow the J1939 standard they follow the 11 bit standard identifier according to my understanding. So my doubt is if i have an engine ecu and if it is used in trucks as well as car. Do they follow different softwares to adjust to these identifiers. In cars do they follow any standard like J1939. Can anyone guide me.