2012 International 7400 low voltage to ecm

I bought this truck it cranks over good but won't start it has really low potential battery voltage of around 9.5 and while cranking 2.5 volts. Vin is 1HTWDAAN9CJ615484 has 7.6 liter engine. Any ideas what would cause this ? I checked all wires with voltmeter and a headlight to make sure it has amperage and voltage to the wiring right before it goes into the molded rubber conduit. All batteries are new and all fuses check good. Engine does crank over well and I can hear fuel pump running.

 

Thank you for reply so it appears I need to test wires at the grey ECM connector pins C46, and C 1, 3,5? The wire shown in pic appears to feed the ECM if it is disconnected my scanner will read only 1.5 volts of battery potential voltage and if reconnect it goes back up to 9.5.