Gas Recirculation Valve (egr Valve) problems of the 2011 GMC Sierra

Engine light symbol message appeared on vehicle during the early part of September. (not quite sure of the date). Dealership indicated that the work was covered under warranty and will require a full day to replace parts. After repair the vehicle seem to operate excellently until the middle part of October. Engine light message appeared again on vehicle. At this time the service manager identified the problem as a sensor overheating. Needed to bring vehicle back when diesel mechanic is on duty. Requested advice for travel. Service manager cleared code. Engine light message came on again in minutes. The next day while traveling engine lost of power message came on within 150 miles from where we departed. Before lost of power a message of low in exhaust fluid flashed on and off. Pulled to the side of the road and turned engine off for about 30 minutes. Restarted vehicle and the vehicle drove well to our destination of 248 miles more. Carried vehicle to a GMC dealership. The dealership identified the following codes: p113a-egr temp 3-4 correlation; p2471-egr temp sensor 4 high voltage; p20cc-exhaust fuel injector performance history. Dealer stated repair could not be address due to other scheduled appointments for a week. Dealership mechanic cleared codes. Engine symbol returned in 25 minutes. While returning back home the vehicle again gave the message low in exhaust fluid and within minutes went into lost of power mode. Scheduled appointment with the dealership again to resolve the problem.