Go on eBay or Amazon and get an ELM-327 module. If it specifies that it works with Apple or Android, get the right one. Then go the app store for your phone and get an OBD II app. The module plugs into the OBD II Data Port in your car and talks to the app on your phone. You can pull codes and clear the computer from your phone or tablet. You can also keep tabs on the Readiness Monitors so you know if they are coming to ready.

The apps come in Free Versions, and Fee Based Versions. You can play with a few free versions before buying the fee-based version. The fee versions allow you to build log files of things like fuel trims if that sort of thing excites you.