In terms of reading fault codes from the engine’s computer, they are similar. However, car health monitors are continuously monitoring the vehicle’s condition as you go about your daily drives, OBD scanners are deployed only when needed and are not continuously connected to the car’s OBD2 port. The difference between them is that car health monitors are more often than not a part of a digital ecosystem and are always connected to your car’s OBD II port for longer periods.