Which OBD2 car diagnostic scanner is the best? How to judge which OBD2 car diagnostic scanner is the best? Buyer should know difference between different obd2 car diagnostic scanners first. Such as its appearance design, communication way, compatibility and functions. And before we buying obd2 car diagnostic scanner, it is better for us to check vehicle model, external device we will use in advance, so that we can buy the correct car diagnostic scanner. And furthermore, in order to get the best solution, we also need to consider the cost, convenience, brand, upgrade and after-sale service of the obd2 car diagnostic scanner.