Need help!! Freightliner with Cat 3406e got me stumped

Hopefully somebody here can help me:

1998 cat 1lw 3406e in freightliner classic

No start

Ecm will not power up

power supply and grounds have been verfied and load tested (keyed hot, constant hot, and ground)

Ecm has been bench tested and ran on boyd caterpillar dyno in corbin ky and is good

Check engine and engine stop lights do not come on on dash but i have confirmed that they do work (bulbs not bad and wires are good)

What am i missing???

 

Yes

i tried a good spare ecm and had mine checked at CAT.

 

I load tested the hots and ground for ecm power supply to 10 amps.

 

If i understood him...The tech at cat told me i had to have two 5 volt datalink inputs to the ecm in order for it to power up. I had never heard this. But i do not have ANY voltage or grounds on the datalink pins on the harness coming from the truck.

 

Yes to both

 

I have not pinned the sensor side of the ecm. Just been focusing on getting it to turn on lol the guys at cat that ran my ecm on their dyno instructed that i only needed pins 4, 5 and 6 verfied and datalink voltage to turn on the ecm.

I admit that i do not know much about how this ecm works or how the "datalink" interacts witj the ecm. But im trying lol