TweetLike mentioned above, use the OBDII to find out what the exact error code is. From there look it up on the internet and it should tell you which side of your vehicle the sensor is failing/failed. Sensors are very easy to replace, DIY type of deal. I have my own tuner which can flash my PCM to any custom tune I want for my truck. It also has an OBDII to read error codes so I am able to troubleshoot a lot of the things myself. If you are really desperate, youtube is very helpful with video tutorials.