iamrich

With my 1999 Suburban I get no fault indicator light, but it just does not seem like I have normal traction and the intermitent ruts left behind kind of tell me it is going in and out of drive. This only happens when I climb a very steep hill. I believe this could be a servo, but do not know how to check this and where to even find the servo.

nic25276

more than likely its the 4 button switch on the dash

4x4van

Wanted to check back in with a follow up. Every time the problem acted up ("Service 4WD" notification) I could not change from 2wd to 4wd. So, after a dealer diagnosis, I replaced the encoder motor with the one from Autozone ($285 rather than the OEM $420). Solved the problem...for awhile. Then after a little over a year, it occurred again. Lifetime warranty on the Autozone part (Dorman brand) so I pulled it and replaced it. Again, solved the problem...for about 6 months. This time, it seemed as if I could hit the dash switch/buttons, and the problem would go away. I also noticed that when I got the "Service 4wd" notification, the dash switch was unlit (no light for 2wd, 4wd, auto, etc.). Read somewhere that the dash switch is a common failure, so I replaced it (OEM $100). Solved the problem...for awhile.

AAAARRRRGGGGHHHH!!!!!!!!

Suddenly, a new problem crops up. I would be driving along, and suddenly the trans would drop out of gear into neutral. Had to come to a stop, go to park (it would grind loudly) and then back to drive and I was good to go...till it did it again. No notification on the dash. Took it to Chevy for a diagnosis. They tell me that the trans is gone, needs to be replaced or rebuilt, at a cost of $3300+. At this point I'm ready to dump the truck, but decide to give it one more chance. Call around, find a trusted place that will replace the trans with a rebuilt unit for $1500. Cool. Drop the truck off, pick it up a few days later, head home. About halfway home, the truck suddenly drops into neutral!!!! This time it won't come out of neutral; I'm stuck.

So I call the trans shop back. Talk to the owner for a few, and he tells me to hit the Auto 4wd button. Bingo, I'm back in gear. He says it wasn't a trans issue in the first place, it was a transfer case issue. (unfortunately, I never asked him to diagnose the problem since the Chevy dealership had already done that. So I had just told him to "replace the tranny"!).

Take it back to the shop, who promptly figure out that the encoder motor is the issue, shifting the transfer case into neutral while driving. I tell him that I've replaced the encoder motor several times already. His answer? He tells me that I HAVE to use the stock OEM Chevy encoder; the aftermarket ones will not last.

So I pull the $285 Dorman encoder motor, and install the $421 Chevy OEM encoder motor. Bingo. 4wd system and trans have now been running trouble/error free for 2 years.

So a heads up; that encoder motor can cause all kinds of burps and glitches with the 4wd system, sometimes with a dashboard notification, sometimes not, and it HAS to be replaced with the OEM unit, NOT aftermarket. Had I known that back in 2009, I would have eliminated several years of headaches, encoder motor replacements, switch replacements, AND a $1500 transmission swap that wasn't needed!

Ian Anderson

There is a very simple answer to the 4x4 indication warning light on the dash, as its telling you that you need 4x4 service... A shop will charger you 100's of dollars for this task, but ALL YOU NEED is to replace the 4x4 dash switch at a cost of a little under 50 dollars (US)..its a very easy installation as well. Simply Pull your negative battery cable, Drop the shifter to the lowest position to give clearance, Lower the sterling wheel as its adjustable to the lowest position if yours is adjustable, Then Snap off the dash ring by hand and pull all the (5) snap in plugs going to the dash off,..
Snap out the old switch and replace it with the new one for your year truck..
........Replace all connections correctly and put your positive battery cable back on and YOUR GOOD TO GO, the computer will see that the problem is fixed...
guess this is a Chevy defect that there is a bad solder joint on the switch is all.. SAVE YOUR SELF 100's of dollar's and do this job your self for $50... JUST DID MINE,....works like a charm now .......No warning light what so ever.,.. all 4x4 functions work like new

IA

4x4van

Glad that worked for you, but as you'll notice if you read my previous post, that wasn't the problem for me. As I found out, the encoder motor can cause all kinds of weird things to occur, and IF it is bad, only an OEM replacement will suffice, not aftermarket.

Ian Anderson

Quote:

Originally Posted by Rich E

The only issue I've ever had with my '07 is this damn error message. It comes on sporadically and will go away when I turn the truck off. I've been to the dealer 3 times for it, but unfortunately I can't seem to get there when it's on so I just tell them the issue and hope they fix they it. It really sucks because it's so inconvienent to get to the dealer. Well they obviously have no idea because it happened again yesterday. Can anybody tell me WTF???

Yes 4x4 Van. I new that was not the same problem you had, just though that others that read this would see that they to could fix the same problem I had as well, as a shop would be So expensive and its an easy repair is ail. Here is a video on YouTube that can be utilized as well. Hope it helps others fix this same problem that a lot of these similar years of Chevy seem to be having....

There are step by step instructions here, Main one to fallow - as in Any electrical connection repair !, is the, make darn sure to remove that Negative Battery Cable first is all... the dashboard is kind of scary to pop off as well, need to make sure to drop that shifter way down as well as lower the steering wheel, as well as to make sure All connections are firmly back in there prospective positions.... hope your back up and running as well now 4x4 Van.. sure did sound like a lot of coin that could have been avoided !.


Ian

Endeavor

Tagging onto this thread... got this same warning message yesterday for the first time in our '07 after going off the paved road onto a level, hard-packed dirt road. Normally, we are in 2wd. I switched the round selector to AWD to let the truck decide when to transfer drive to which wheel. AWD indicator would not light up, only 4HI. Warning message continued to be displayed with a few restarts of the truck. Now in 2WD mode, no message.
A little back ground: before traveling to this destination, I noticed the buttons for dimming, fog lights, lights and drive selector ***** were misaligned. It looks like the button panel got knocked in by a knee or something. I was able to push in and pull it all out so it is now flush again... wondering if this switch (as I've read above) is now bad?
Thanks!

Ian Anderson

Also replaced my Dash Switch,. Still had the problem later on,.. then I traced it back to the Modula its self on the transfer case, Replaced that !... Found Blown Fuse,..Fixed that...now I get 2 and 4 wheel drive,... but Cant get Low range, and then it all goes out again until I Un hook the negative battery cable and it all comes back until I hit Low range again... MAKE SURE to unhook Negative Cable BEFORE replacing Switch Or module as well.. OR IT COULD BLOW THEM ALL..

The net page I found said I have to clear the computer by unhooking one of the modules behind the glove box and the Battery again for NO LESS then One half hours,.DO THIS 5 times tell it clears,... I have a great line on where to by the Transfer Module as well as the switch.. I can post that if you like.... did the hole job for under 150 Bucks'... Shop will charge 1000's ...Buy the parts your self...

4x4van

I never had to clear the computer; it shouldn't be necessary, and disconnecting for 1/2 hour 5 times is way over the top. The only other thing I would caution against is the "great line on where to buy the Transfer Module..." If you are referring to the transfer case encoder motor, stay away from aftermarket (even Dorman); It won't last and will give you ongoing headaches (you still don't have low range, right? So perhaps you haven't yet done the whole job for under 150 bucks?). The Encoder Motor is one part that only OEM will work. Trust me, been there done that! Yes, the OEM Encoder Motor is expensive. Yes, it's worth it.

After several years of 4wd problems, I have now had 2 years, completely trouble free. THAT is worth the cost of the OEM Transfer Case Encoder Motor!

Ian Anderson

.....Yes its true, I don't have 4x4 Low working Yet fully...Not sure why !..the Transfer Case Motor was indeed a (Dorman) Motor and its in good working order New,.. SO WHY DONT I have 4x4 low and Why does it take out the hole operations and ONLY SOMETIMES, ..not even getting it out in the woods to test it but here in the driveway,.. is there an explanation to what may be casing this besides the (Dorman Motor) like the Web site said not being good enough ?, ..

After Installation- IT ALL WORKED WELL, but after letting it set for a day and then I still had 4x4 and 2x2 but then as I said, I would switch it to 4x4 low and that problem would then happen, after clearing the Computer IT ALL WORKS AGAIN.....Until I switch to low then the hole thing starts again now.. there has to be a Conformant in the Computer, Why else would it me Intermittent like that now.. and the 4x4 and 2x2 are Working Until then.

Here is the Web page I was referring to as well,.. as I can tell, that's the TCCM Controller that needs to be cleared as stated....

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