Pushbutton 4x4 Problems

Before I knew any better, I purchased a used pushbutton 4x4, 2001 GMC Yukon. I now frequently get a "SERVICE 4WD" message on the dash. What should I do now? The thing clears up when the vehicle is restarted. The dealer doesn't read a code and the problem will not repeat while it is in the shop. Should I purchase a OBD scanner and leave it connected so I can see if the code shows up while driving and I get the message? What is typically the failure mode of these systems? When this occurrs, I cannot shift the 4x4 system. I'm afraid I'll get locked up in 4x4Lo at some point.

Reply to
clwomble via CarKB.com
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Dont worry about it getting locked in any 4x4, because this sounds like your computer (Transfer Case Control Module) is about to take a crap or the Encoder Motor (the motor that shifts) is taking a crap. If its the computer it should go back into 2hi by default. If its the Encoder motor I dont know what to tell you. We had the same problem with our 99 Jimmy it has the 4 button sytem (auto4hi)

Reply to
Adam F

Oh the wonders of push button 4x4 and the reason I would never own one. It is normal for the service light to come on when code it set and the light will reset when vehical is restarted but code should still be readable from memory. Try scanning it while light is on.

----------------- TheSnoMan.com

Reply to
SnoMan

In that year, the most common problem was the dash switch. There are two types of "trouble codes". Current, and history. In your case, there is almost always a history code 2725 if it's the dash switch. If you don't have any codes in history, the other option might be that you need to have the ATC (automatic transfer case) module reflashed with the latest software. The dealership will have the ability to do this. The maximum that they should charge you for reflashing the module (if in fact there is an applicable update) is .6 hrs at whatever their labour rate is.

If you happen to get an 0327 code either current or history, you may have an issue with the position sensor in the encoder motor. This issue was not a big problem in the early years, but now we see it on a regular basis. In this case, you remove the encoder motor and replace "only" the position sensor.

Hope this helps.

Ian

Reply to
shiden_kai

I had the same exact problem plague me off and off for the first 6mos of owning my new 2003 Silverado Z71 - it took about 6 trips over 6 months for them to replace the pushbutton control module. They reset the computer several times because they never found anything wrong - finally I managed to get it in there when the error occurred - fortunately it never came back once they replaced the switch. I found if you pull the fuse to the 4WD module,leave it out a few seconds and then put it back in and restart all would be fine - that told me it was electronic and not mechanical. You are correct in assuming that whatever mode you are in when the error occurs you are stuck in, but removing/reinstalling the fuse would be a temporary fix that only takes a minute to do.

Good luck getting the issue resolved.

Take care, Kevin

Reply to
Kevin Klein

My 2000 had this problem three years ago. After reading this NG I knew the problem with the switch was so widespread that others had even come up with a way to fix the switch. I bought a new switch for $50 and installed it myself, I haven't had a problem since.

Al Bottoms Up Divers

Reply to
ajtessier

A generic ODB II scanner probably won't pull the code as the transfer case is not emmissions related. You would need the GM tool for scanning non-emmissions codes. I bet it's an expensive tool because it is not mandated by law to be compatible with other manufactures like the emmissions items are - sort of like ODB I.

Reply to
Ed H.

My 2000 4x4 Silverado 5.3 LT had the "Service 4x4 message".... in 2nd Year...

Problem was cold solder joints on the 4x4 Push Button switch...

Replace the $50 Push Button Switch unit & the Prob should go away ??

Reply to
Dennis Mayer

Reply to
clwomble via CarKB.com

Al,

My 2000 is doing the same thing. When I first start it up, I get a Service 4x4 message for abour 2-3 seocnds. It's intermittent of course. I took it to the dealer with a laundry list of problems and they said they'd fix it. I noticed the next time I used 4 hi, that the issue started coming back again. I am not sure if they cleared the codes or replaced the switch as the switch looked physically the same so for $50 I am thinking I will just go ahead and replace it. Was replacing this an easy job? Did you get the switch from a dealer or online?

Thanks,

Derek

ajtessier wrote:

Reply to
genius

I got the switch from a dealer but the parts guy was a dive buddy and I got a it for what it would have been sold to a repair facility. Installation was simply:

1) Remove dash trim around switch (no tools - it pulls off) 2) Remove a few screws holding the switch 3) Unplug the wire harness 4) Plug in new switch and reinstall

Al Bottoms Up Divers

Reply to
ajtessier

And lets hope the new ones are better then the original!

Al Bottoms Up Divers

Reply to
ajtessier

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