My truck is a 2000 VN770 with a DDEC IV 12.7L.
Has inactive code I cannot find anywhere.
MID 128 SID 051 FMI 3 (inactive 13 times)
Text fault says- Engine Aux output driver3 Electrical Fault.
No idea what that means. No CELs truck runs fine.
Connection to stage 3 engine brake solenoid is bad.
Bad connection inside ECM
Bad connections from ECM to wire harness.
Bad wire harness ( broken wire)
Bad wire harness under valve cover.
Bad connection to the solenoid.
Looks like somewhere connection got loose and when engine vibrate it's throwing codes.
Gotta love the electronics that Engineers today put in between you and "it."
My daughter has a 2915 Ford Flex.
So again, in between the wheel and the rack, they put an electronic controller, and a motor.
Hydraulics and pumps and lines aren't Techie enough for you?
They never fail.
This Flex was 4-5 years old and total steering crap out.