Dealership cant fix truck... what to do next?

Truck has red engine light on and is not drivable. Took it to 2 freightliner dealerships and they cant figure out what is wrong with it. It is now sitting in a third dealership being checked out, but im scared they might not be able to repair it either... what does one do in this situation? Do people just "throw away" their trucks? This is a 2018 cascadia with about 700k miles on it and it looks like its a computer issue... any input is greatly appreciated

 

The first 2 times, we were able to drive the truck to the dealership before the red engine light came on. It was able to run for a bit after shutting down and sitting for couple of hours, so we managed to drive it to the dealership (with only the MIL light on). Both times the dealerships said they couldnt find the issue because there was no active code (even though the truck kept shutting down every 100-200 miles)

Truck finally shut down for good and no amount of waiting would make it work again so had to get it towed to nearest dealership where it is currently at

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What do you do if you have a computer issue

 

The last dealership told me it was a computer problem but couldnt pinpoint exactly what the issue was since there was no active code to troubleshoot