Limp mode question

[PSD]

Looking into buying another 6.4 but had a limp mode issue. Says " it goes into a limp mode after driving under load"

Haven't looked at the truck yet to pull codes.
Any ideas? Im lost

 

[CT9AIX]

That's a pretty broad question. Pull confirmed and pending codes, or go for a test ride and data log to get an idea of what's happening. Something tells me if it goes into limo mode, it will have some codes, even if the light on the dash is not on... lets us know what they are and I'm sure someone will have an idea

As a start, is the truck stock? Maybe after a hard run one of the EGT sensors in the DPF is seeing some extreme temps and causing it?