On the front of your air-intake, under the hood a sticker placed there gives you a rundown of what all of the codes mean. Yes 17 is the stock exhaust temp sensor and yes you can change it out and it will (if the new one is good, should read 200-400 ohms unpluged to be good, I have bought a brand new one that was bad = closed cuircut) eliminate that code and that portion will run better. It is best to hook the sled to a analyzer which your dealer should have, I was able to play with one the other day when my 09 had a issue, this system is pretty neat......anyway the analyzer while tell you exactly what is wrong, then you can swap the part without throwing a bunch of coin at possible problems, clear the code and you are on your way!