Car repair codes are used to determine what problems a car may be experiencing and how to go about repairing those issues. The codes are obtained when a mechanic performs a diagnostic test on the vehicle.
When a mechanic performs a diagnostic test on a vehicle, an alphanumeric code is provided that helps the mechanic determine the type of issues the car is having. The diagnostic test is generally done after the check engine light comes on, and the resulting alphanumeric code narrows down the reasons as to why the check engine light came on in the first place.
After the code is provided, the mechanic is able to perform other tests to determine the exact cause. The mechanics may also use the code and other information provided by the car's owner to help determine the issue without the need to perform further testing.
Many auto parts retail establishments, such as Auto Zone or Pep Boys, have code readers that may provide this service to patrons free of charge or for a small cost. This could be helpful to individuals who perform car repairs themselves. Some auto parts stores also refer their customers to local auto repair facilities after performing the diagnostic service.