Another Service 4WD Question with a twist

[stowe]

Hello, I have a 2002 Yukon, when I i place it into 4wd high the truck shifts to 4wd and drives fine, after a few more minutes of use the service 4wd light comes on , the truck is still in 4wd but then I am unable to change back to 2hi without shutting off the truck and restarting. I changed out the selector switch already, any suggestions? The truck does not jump out of 4wd hi I am not sure where to look next, with snow around the corner I would love to get this sorted. Thanks for your help

 

[Wake]

I'm thinking the encoder motor on the transfer case is the next easy thing to check.

With the truck shut off and the key on can you hear the transfer case under the truck shift between the different modes selected?

If it's not that then I'd wonder about the computer module for the 4wd system. In 02 Trailblazers had a problem with the TCCMs which would cause symptoms similar to what you are experiencing.

 

[BarnyardHoe04]

Hello, I have a 2002 Yukon, when I i place it into 4wd high the truck shifts to 4wd and drives fine, after a few more minutes of use the service 4wd light comes on , the truck is still in 4wd but then I am unable to change back to 2hi without shutting off the truck and restarting. I changed out the selector switch already, any suggestions? The truck does not jump out of 4wd hi I am not sure where to look next, with snow around the corner I would love to get this sorted. Thanks for your help

I have been having a similar problem. My error light comes on in 2wd and wont switch to any 4wd setting. But if I turn off the car, the problem goes away and I can then engage 4wd. My buttons have previously been replaced but that was years ago when the car was new in 2005. If I bring it to the dealer would they be familiar enough with thte situation to properly diagnose it, or do you think they would just try to sell me a new part regardless, even if the problem lay somewhere else?