CM870 ambient temp problems

[Shaman870]

(09-17-2025 )Wesoja2 Wrote:  I never thought of that.. I wonder if dealership flashing stock file again with ECM in the truck would restore that address or not.

Yeah I found out how quirky they can be. Hopefully he’ll chime in and have an idea of what it can be. I’ve scoured your site and others and have yet to find anyone with this issue. Plenty of 870 demandate issues but this one seems to be unique

I've seen couple demandating progs where 1 parameter tweak affecting that temp sensor reading, it may show freezing when hot outside. Also when flashing stock calibration - its in the state to receive a cabcontroller information which is supposed to be saved before any ECM-related "adventures". I am guessing people tweak it to make ECM think that it is freezing outside, so "magic valve" would stay closed during engine operation. Also if that sensor is disconnected, program will guess and rely on other data and use "constants", so even if sensor is disconnected, it will run fine. But again, may be sensor itself is providing messed up data. Those things cant be answered 100% accurate by forum members guessings.