I have an 08 suburban z71 5.3 and it keeps throwing a c0374 she you try to use the 4wd. Up until 07 it was a bad wiring harness but in 08+ it means that the general system temperature is too high. But it will do it as soon as you start it and take off in the snow and it gets pressure put to it. If anyone has run into this before let me know what you did to fix it. I've searched it and couldn't find anything.

 

Has the transfer case fluid been changed within the last 50,000 miles? If not best to have it changed.

 

So not long after i initially posted this ( apparently with a dif username since I couldn't get logged back in) the afm screwed up and a lifter collapsed and I ended up rebuilding the motor deleting the afm. So now I am back tryin to get the 4wd working again. I changed the tranfercase fluid and there was a decent amount of fine metal particles stuff the drain plug. And the fluid was dark. I messed round with it and got it to kick the service 4wd again with the new fluid. I'm not sure whether I just need to try driving it a bit to circulate the fluid or if I need to remove a sensor or what. Any help would be appreciated.

 

Any ideas?