I have a little IC bus that has been starting hard . Yesterday it died and driver left the bus in the yard . I startd the bus and let it run and took it out for a test drive . Told driver nothing wrong . Today the boss went to start the bus and it wouldn't start . So I went out and it started and i let it run and the driver took it over to another building and it died Wouldn't start . I got it going and on the way to the shop it quit . I hooked up my laptop and the only real issue said low IDM relay voltage . I cleared the codes to see if the IDM relay would show up again . Well this 571 came up saying something about number one was an issue but not worry . I know a bad relay or power to the relay will kill an engine . So do I need to take care of this issue