From another forum...

[Colter]

(09-24-2021 )eggtrucks Wrote:  This is from a 2018 X 15 With 176,000 miles


What caused that? Turbo failure?



We are not even sure at this point. We towed the truck here Were told it was overheating. It had a misfire code for a injector. And it had a hole in the flex pipe after the turbo. It ran fine once we unhooked the exhaust. So I can’t believe the engine doesn’t shut down before this happened but it may have been a combination of things. I wish we could get a better story on the truck. Supposedly it had a problem And was at the dealer for three weeks and they said they can’t find anything wrong

Does this engine idle a lot? higher RPM idle?

There's a TSB out from Cummins in spring 2022 about trucks melting the aftertreatment modules, Cummins recommends an 800-900RPM idle now. This is in direct contradiction to the everything else they have stating a high idle of 1400. We saw a few exactly like that last fall. I will look up the TSB number.