Cummins ISL CM2150 shutdown on grades

[Asemastertech]

We have a Cummins ISL CM2150 that is going into shutdown mode on steep grades. It has mandates removed. Fuel filters replaced a couple times with no change. No history or current trouble codes present, gauges all in normal range, no warning lights come on. When shutdown occurs, it loses all power with no throttle response, it continues to run at idle until the vehicle comes to a stop and then shuts itself off. It only has 67k miles on it and it runs great other than the shutdown problem. It restarts immediately once the key is cycled off and then back on. We have been watching the data on a Autel 908CV scan tool and everything is in normal range. It acts as if some pressure or temperature limit has been reached and it is going into self protection mode. EGT is maxing out at 1170 degrees. Our next step is to buy a new ECM and get a new aftermarket program. We have two questions: Does anyone have any experience with this particular issue of complete shutdown with no codes? Who is the best person to talk to about getting a quality program for a new computer? Thanks for any good advice!