1999 Tahoe 4X4 issue

[Ermerins]

I have a 1999 tahoe with a strange (to me) 4x4 issue. With the truck stationary in neutral and the brake pressed, the 4x4 system will shift perfectly from 2hi, 4hi, 4lo and 4auto and back. When I drive for a bit in any setting other than 2hi the service 4x4 light comes on and will not let me shift out of 4wd until I come to a stop, shut it off and restart. I suspect there is a speed sensor someplace that is acting up, but maybe something else?

 

[Miami-Dade]

Welcome from Miami Beach Scott!

 

[OR VietVet]

Welcome to the forum from Oregon.

Maybe this is what you are talking about.

https://www.rockauto.com/en/moreinfo.php?pk=9667108&cc=1353721&jsn=2386


Better hope it isn't this:

https://www.rockauto.com/en/moreinfo.php?pk=6355122&cc=1353721&jsn=2320

 

[Fless]

A good place to start would be to get the 4x4 codes that are setting the "service" message. You'll need a fairly advanced scanner and some auto parts places have them to read the code(s) for you.

 

[Ermerins]

I have a 1999 tahoe with a strange (to me) 4x4 issue. With the truck stationary in neutral and the brake pressed, the 4x4 system will shift perfectly from 2hi, 4hi, 4lo and 4auto and back. When I drive for a bit in any setting other than 2hi the service 4x4 light comes on and will not let me shift out of 4wd until I come to a stop, shut it off and restart. I suspect there is a speed sensor someplace that is acting up, but maybe something else?

After much frustration and several shops I traced the problem to an electrical fault in the harness. I repaired the break and no more light. System works as it should. YAY!.....now on to other problems.