Car code readers are relatively inexpensive, making them a worthwhile investment if you want to pinpoint an issue with your vehicle without having to take it to an expensive mechanic. A car code reader allows you to read and clear codes, view basic parameter IDs, check and reset readiness monitors. This gives you a good way to tell if the problem is something you can fix easily before shelling out to a car shop, potentially saving you hundreds, if not thousands of dollars.