Peterbilt 386 starts and dies immediately

[shawn21998]

Hello everyone new user here long time lurker hoping y'all can help me out with this one. I have a 2013 Peterbilt 386 with a ISX15 CM2250. Truck will start right up and die immediately. Only active code is SPN 168 FMI 1 "SAE-Battery potential (voltage) data valid but below normal operating range - Most severe level" from component 128. And "Power supply ignition voltage too low" (spn 627 fmi 4) from EC-60ABS. Batteries are new and code still comes up with charger connected. I have cleaned battery and starter connections and checked grounds. Performed voltage drop on grounds at engine and chassis with around 1v drop during cranking. All fuses and relays seem good. Lowest voltage while cranking is 10.7v at batteries and 7.2 at starter. Hoping to get a diagram for OEM connector at ECM so I can test voltage at ecm. I have jpro and use cummins quickserve but the battery code is OEM and quickserve has no information for that code. Any help is greatly appreciated.