ELM, Scanners, AutoTap, Can-Bus
Do not be a swapper of parts, if you have an OBD-II you could connect to the diagnostics port on your car, whether it's a Ford, Mercedes, VW, Audi or any US Market automobile. You may learn about the problem is so you can begin your automobile repair. There's no need to substitute parts and hope that you repair the problem when you can already own all the tools you need.