I hope this forum can help on this. I have a 2004 Tahoe, recently the "service 4wd" came across the diagnostic center in the dash. None of my 4wd lights by the buttons were on not even the 2wd one. They would not work. I drove it that day and then it went off? I dont have a engine light on or anything.
Any ideas?
Thanks
Dave

 

If the lights were inoperative in the switch, I'll bet that the switch is your problem. I had the lights doing funky things in my 4x4 switch, then the "service 4wd" message came on. I replaced the switch and it's been good ever since.

 

 

Go to your local parts store and ask to scan for a code, record the code.
Mine does weird things too and a simple restart clears it although I have codes for the encoder motors

 

Thanks guys, this is the second time it has done this. The first time I also had a tire a little low when I aired it up it went away? Probably not related is my thought. I have a scanner but had not had a chance to check it I will see if I can get anything from it if not I will get it scanned. I also didnt know if there would be any codes since it just showed up on my screen and no "check engine" light on or anything.
I hope it is not the encoder motor that sounds expensive. I think I had something simular replaced on my 1996 a few years ago but I don't remember for sure.
again thanks
Dave

 

On an 04, if the lights on the switch are out, check fuses before you do anything. It could be a switch, but that's much more common on 99-02 models. You may have an encoder motor issue if your fuse is blown. Also, the dealer may have a TSB for a reflash of the TCCM, regarding intermittent 4x4 switch issues. May need to call the dealer with your VIN to check.

 

The sensor the encoder is probably bad. I replace them all the time. Gm has a sevice bulletin on it.

 

I've heard of the encoder motor sensor failures also...is that more common on the 03+ or is it all of them (99-07)

 

It's more common on the 03+ models.

 

I still have not pulled the codes I will get some more info thanks again guys