“It’s nice knowing what’s wrong with the car before you bring it in for service.” Men’s Journal aims to feature only the best products and services. If you buy something via one of our links, we may ...

Then plug in a diagnostic tool to your OBD2 port and find out what’s wrong—or at least narrow down the possibilities. If you’re not sure which OBD2 code reader to buy, we've found the perfect one for ...