ISX15 CM2250 Engine keeps shutting down problem ('12 KW t660)

Ok, I really need ya'll help! ISX15 CM2250 ('12 kw t660) broke down wednesday. Dash displayed Exhaust SCR/DEF Service Required. Red Engine shut down light would come on and shut down the truck. Driver attempted to drive, after a minute truck would shut down. Driver waited 4 hours for tow truck to show up. It was 125 degrees outside in AZ. After 30 mins. of the truck cooling down, it would turn on for 10-20 mins as long as he didn't attempt to do parked regen. Anytime he attempted to do park regen, truck would shut down immediately. Then after a few hours, the dash displayed "CIRCUIT FAILURE,SEEK SERVICE IMMEDIATELY" in red letters. Then the truck wouldn't even crank. Finally the tow guy showed up and got the truck towed 45 miles to a shop, they looked at it the next day. Next morning, truck fired up fine, tech unhooked trailer and drove it into the shop. I told their tech to trace the wiring to the ECM and make sure there's no short or wire peel. I also told him to check battery box fuses, inspect wiring going to after treatment system and carefully inspect DPF & SCR. After about 5 hours of diagnostics they told me the fuel injector dozer (not def dozer) is bad, it's leaking. They replaced the fuel dozer, ran a forced regen with the computer. And also replaced both of the fuses in the battery box. They said the box was moving (that holds the fuses) and zip tied it down. After a $2,050 shop bill, Driver drove the truck 700 miles, went to sleep in New Mexico. He said it was kind of cool, so he shut the truck down. When he woke up in the morning, fired the truck back on. Same problem! The red engine shut down light came back on, and now the engine in derated. When he presses the pedal, it don't go past 9k rpm and truck won't go over 5 MPH. Now a road side guy showed up and he's looking at it, as I'm typing this. Truck displays DPF/SCR Service required but the DPF Light is not on, on the dash. What ya'll think is going on?