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I have a 2019 W9 that has me absolutely lost.
X15, intake air temp randomly jumps to 492.8, its the same every time, and then the Turbo Compressor Outlet Air Temp (calculated) jumps up to 27 thousand degrees, Yes 27k deg.
Truck goes into derate.

I have changed so far,
new ecm, stock file, OEM.
New engine harness OEM
intake temp/pressure sensor OEM tried several
Exhaust gas pressure sensor

ambient air reads correctly.
exhaust gas readings are correct as well.

I have done many other checks including even isolating the intake temp wire from old harness, and grounding it to see what ecm says, and even supplying full 5v and seeing what ecm read.
Never went to 492.8 deg.
Also ran new wire right from intake sensor temp wire, right to the correct pin on ecm, i think 62. That made no change.
Thats when I opted for new ecm and harness.
Im so lost and at this point ive spent so much time and money on stuff I just dont know what else.
Help!

492.8-F = 256C.

- It could be the turbo inlet temp sensor (or wiring, or voltage supply) acting up?. I know that it is used to assist in calc. of the overall air inlet temps, and if it reads off by too much, the engine will start to do some odd things. The turbo inlet temp should NOT be reading the same as the ambient air temp when the engine it warmed up. It will read quite a bit higher because it reads the inlet temp + how hot the turbo is getting on its face. This is used by the ecm to help estimate the turbocharger heat absorption rate.

- or Maybe an external interference like RF (radio) or other source of noise interference comming from somewhere?.

- or maybe a +5volts sensor supply somewhere getting shorted to +12volts intermittently?.

When did it start acting up?. Maybe some more history on it?.

and are you allowing those morons at the truck wash places spray/clean under the damn hood ?. --- Another big no-no!.

Also, What is the engine ser#?.. and what program is in the ECM?.

.. and is it De-mandate?.
If it is de-mandated, then copy the program out of the ecm and e-mail it to me for a proper review of what someone did in there regardless of it being the issue or not. More than 90% of all programming of this type is quite harmful, it causes progressive damage, and severely shortens overall engine lifespan.

Where are you getting your sensors from? If they are not directly from the dealer they could be Chinese knockoffs. They will look EXACTLY like an oem part, even the box is identical. This is such a problem that cummins has come up with a hologram to put on all genuine parts boxes so we can tell the difference between genuine and a fake.

https://quickserve.cummins.com/info/qsol...Label.html
.
Non genuine sensors are known to be erratic and unstable.