Cat 3126 I think it's a 2002. Its in derate with a high intake temperature. This truck also has an intermittent code for injection actuation pressure signal erratic. Another thing worth mentioning is that the owner of this truck couldn't get the cover off his air filter housing to change his air filter for about 2 years, not sure how many miles he drove it like that, I'm guessing 20K-30K. He changed the housing and installed a new filter at my shop 2 days ago. I've never ever seen a filter this bad. I don't know if all 3 of these things are related???
Not sure about CAT but high intake temp readings are a sign of the turbo not being able to push air properly for most engines.
* blocked intake.
* Blocked exhaust.
* Excess soot damage to turbo because of excess engine soot, Usually looks like acid has etched the exhaust or VNT/VG blades on the turbo once taken apart.
* Carbonized turbo bearing from excessive heat and poor air flow, or someone shutting off engine a few times with turbo hot.
* Blockage in CAC.
All I can say is that engine abuse = engine problems. Yes they are likely related. - Jump over a dollar to save a dime trucking.