Modern vehicles’ sophisticated electronics go far beyond the simple car mechanics most of us grew up with. Now, OBD, or on-board diagnostics, diagnoses almost every issue within your vehicle. Whether your engine is running low on oil or spring is out of place, the OBD steps in to diagnose the issue.
Onboard diagnostics provide near-universal codes, allowing users to understand what is going wrong in their vehicle. By understanding the differences in OBD versus OBD II and the different code readers available, you can address almost any issue that arises in your car.
As the name implies, diagnostics are the primary purpose of OBD. When a car’s sensors decide that something is amiss, they trigger a message known as a “trouble code,” which may manifest as a “check engine” light or another warning on the dashboard. OBD scanners can check these trouble codes to determine exactly what’s wrong, and clear them from the computer’s memory once the problem is fixed.
The trouble codes are just that, though: Codes. Instead of a diagnosis like a “loose fuel cap,” you will see a string of letters and numbers that is incomprehensible without a reference. Trouble codes start with a letter and include four or five numbers, which together point to the specific subsystem and what problem it is experiencing.
Some OBD scanners come preloaded with definitions for these codes, but otherwise, you’ll need a list like the one that can be found on our computer.
Note that in addition to the generic codes that apply to all cars, individual manufacturers have their own specific codes. Finding these can be a bit trickier, as not every manufacturer is entirely comfortable with the idea of releasing them to the public.