2014 T800 isx12

[Crf]

Looking at a2014 T 800 isx12 400st
3.55s F014E310C-Las ult 2pedal Tran
600000mile
Came out with compressed gas motor
but has lately been switched with a salvage yard they say it ran good after the switch but is now stuck in derate. Sensors all appear to be factory red
Truck is overall very clean
Any thoughts will be appreciated

[Rawze]

start by finding out what faults are in the ecm for the derate.

A full egr-tune-up would help too.

fuel pump will need rebuilding at that mileage as well to prevent entire engine grenading on you.

[Crf]

Will the engine ECM have past history
Like hours and miles?
Just scared of the unknown with it being a transplant motor
Do I need insite to retrieve codes ?
If not how do I get them?

[Kingman11]

Insite should get you the codes.