Our EGR Blocker Plates for 2001 - 2005 Chevy GMC 6.6L Duramax LB7 LLY will keep soot out of your intake and excess heat away from your coolant. These will usually throw a DTC after it is installed and a "Check Engine" light on the display panel. To clear the code and shut off the light, LB7 trucks can use EFI Live tuning, and LLY's can use a PPE Standard tuner. Most users report that the light will go out after a short period of time on it's own, leaving only a DTC in the system that won't cause any issues or problems. These are designed for race purpose only.