I noticed that my high idle has stopped kicking on. We have two of these trucks and they can be sitting side by side, the other one kicks on and mine won't. Both trucks are the same except mine has the DC winter front. Took it to the dealer, diesel tech can't find anything wrong, calls tech line (whatever that is) to get the peramaters for the readings on the ECM for ambient temp and block temp and the guy on the tech line says "have no idea, thats supposed to be preset in the ECM" My diesel tech said to bring both trucks in so he can compare them.
I thought you guys might know the numbers or what might be wrong. Theres got to be an easier way. I'm alittle nervious about them flashing the computer because I get pretty good mileage and it runs good, I'm not sure high idle is that important to me. LOL Thanks LCH

 

if my memory serves me correct, the ambient temps must be below 30 degrees and the engine not at operating temps. (190*) in order for the auto high idle to activate.

that being said, mine is very inconsistant in it's operation as well, sometimes it does it, sometimes it won't. can't really figure out the patterns yet.

good luck

 

The one with the winter front is trapping the warmer air in the engine compartment, so the "ambient air temp" sensor isn't seeing the colder air that the one without the winter front is.


phox