I tried looking into possible fixes for you but everyone is saying to load a previous save on which you vehicle summon worked before. If this is truly the case then it sounds like corrupted save data is the culprit here. I would be interested to know if it does the same thing if you were to fresh install the game and then load the same save. If it still happens after that then it is truly the save data. If reinstall fixes it then it's a corrupt game file.