Hi everyone, I finally tracked down my buddy tonight and got him to use his code reader to see what is causing my SES light to come on. I got a P0401 (insufficient EGR flow) code. I had this code a few months ago and took my truck to the shop. They cleaned and re-used my EGR valve, and not even a week later, the SES light came on and has been on since. I'm assuming then, that my valve is no good and it needs replaced. Just wondering what everyone's thoughts might be on this.