To use your scanner, first make sure your car is turned off, then plug it into the port. Next, turn your car back on and enter any information requested by the scanner—in most cases, you’ll need to provide either your car’s vehicle identification number (VIN) or your car’s make, model, and year. Next, go to your scanner’s menu and select the option for “active” or “pending” codes.
If your scanner returns any trouble codes, you can find out what they mean by looking them up in an error code book or consulting reliable online sources. Then, depending on the nature of the problem, you can decide if you want to try and fix your car yourself, or take it to a mechanic.