OBD2 trouble codes are part of a troubleshooting system that helps you track down the source of your engine’s problems. For example, if the engine’s computer recognizes a malfunction during operation, it isolates it, translates it into a code and saves it so you can access it. You retrieve it using one of the methods outlined here. Let’s say the code indicates a too-rich oxygen-to-fuel ratio. Look this up in a repair manual and you’ll see this is usually liked to a faulty oxygen sensor. Replacing it solves the problem and the code resets.

Retrieve OBD2 Codes Using Your Ignition Key

Step 1

Turn the ignition key “On” and “Off” without cranking the engine. How many times you do this depends on your particular vehicle. Most Chryslers require five times; other cars require three. End with the key in the “On” position. Start the sequence anew if you accidentally crank the car.