If your vehicle was manufactured after 1996 and sold in the USA, it contains an On Board Diagnostic (OBD) computer that captures information about how it’s running. OBD II is version 2.0 of the standard for communicating this information for cars and light trucks since 1996.
The information tracked by the OBD II system was originally intended to monitor the engine’s emissions and track down problems that caused cars to pollute more than normal. Today, however, manufacturers have extended the standard to contain a lot more data about problems and performance, including ABS, transmission, engine problems, etc. If there is a problem with the car your car’s “check engine” light will go on and in most cases code or codes are stored. You will need an OBD II reader in order to scan the codes from your car’s computer.
These OBD II scanners will display the code and depending on the scanner’s type the description will be displayed by the scanner, or you may have to look it up in a booklet or online.