Hey guys, I'm 300 miles from home, and this morning, my Jimmy was in 4WD LOW(it did this on it's own), when I started it. It took me several attempts, after restarts, of getting it into 2WD high. After I stopped somewhere, I came out, and it was back into 4WD LOW. It took about TEN restarts this time, before I got it back into 2WD(it won't even ATTEMPT the change, without restarting). ALSO, I noticed that the 4WD LOW button is flashing ~sometimes~, while I'm driving, like it's TRYING to switch into 4WD LOW(BUT, it's not successfully doing so, while I'm moving).

Any ideas?

I've got the 4 button system. I pulled the switch, and disconnected it, and also pulled the 4WD fuse.

Should this get me home safely?
Why does this sh*t always happen when you're far away from home!

 

it sounds like its in the transfer case, however just to make it home i would disconnect the 4x4 actuator. its under the battery tray. make sure to plug the vacuum hose with a bolt or something.

 

It sounds as though you have an encoder fault. First though, I would disconnect the TCCM (behind passenger side kick panel) as well as the electrical connections at the encoder motor on the transfer case, check them for corrosion, and clean as necessary. Also, try searching for NV236 or NP236

Is your service 4wd light on?

 

The Service 4WD light has been sporadically coming on for months, even though 4WD is (was)working. With NO codes stored(at least not that Advance can read).

Now that I pulled the fuse, and the 4WD switch, "Service 4WD" is permanently on.

I recall that when I first got it, it had some 4WD issue, and I pulled the TCCM, and it was corroded pretty bad. I'll do that again, when I get it home.

Do I really need to disconnect the actuator under the battery, to drive it home?

Will it damage something if I don't?

I'm in downtown Nashville, with minimal tools(I probably need a deep well socket to get the battery block out, and I think I only have regular sockets with me). It seems to be running fine now, with that stuff disconnected. I don't have to drive home until Thursday, and I'm getting internet access at the library, so I'll check back tomorrow, for the actuator answer.
THANKS guys. I appreciate the help.

 

The TCCM is not accessible by the scanners used at most autoparts store. It takes a Tech2 or equivalent high feature scan tool to communicated with the TCCM on the Auto4wd optioned vehicles.

Is it in 2HI now? If so, you should not have any problems.

 

Yeah, it's in 2WD. I stopped at an Autozone, and had the codes read, but don't have them with me now. I'll post them later. One was about a secondary air pump not functioning properly(PO410, I think), and the other codes was tranny related(PO17??). But now that it's in 2WD, it sure seems to be shifting properly. NOT that it wasn't shifting properly before, but the guy at AZ seemed pretty concerned over the tranny code.
Thanks again.

 

So, I got home just fine...

I pulled the TCCM today. One "lug" was a little bit corroded, but not that bad. I cleaned it, and put it all back together. It wasn't putting itself into 4WD low, but...

Firstly, are the TCCMs all the same size/din plugs, from 95-2003???? Because I swear we salvaged the TCCM off my wrecked 1998, but it only has ONE plug going into it(whereas my 2001 has two)(OR, am I confusing the TCCM module[in my 1998 "parts box"] with another module?).

Secondly, after I replugged it all, it was only going into a "4WD mode", when I first changed the 4WD switch. Then, it wouldn't change modes again, unless I unplugged, then replugged, the 4WD switch.
Switch?
TCCM?
Other?

 

My '99 has 2 plugs.

 

check the tccm,i had a similar problem,seem my door was leaking and the hassness
was geting wet and caroaded the harness.it would shift into 4wheel high and then into 2wheel hight all buy its self,so i cut the harness and replaced it and cleand all the pins and seem to be fine now,best of luck to you

 

It depends on what transfer case you have concerning how many plugs it will have in it. The NP233/NV233 TCCM is not interchangable with the NP236/NV236 TCCM.