Visit again to the Dealer - 4wd issue

BobbleSmitty · Post by **BobbleSmitty** » Wed Oct 05, 2005 12:18 pm

I tried engaging my truck in 4hi today and nothing happened... It stayed in 2wd. The light didn't turn or anything. Then I tried 4lo from nuetral and it worked just fine. Then I tried going from 4lo to 4hi and it went right back to 2wd?? I took it in to the dealership and left it there, i'll see what they do. Any ideas on what may cause this??

Thanks

-Bob

Blaze One · Post by **Blaze One** » Wed Oct 05, 2005 1:48 pm

there are numerous problem with our 4wd system . mine used to do that and then eventually I started the truck up one day and it was locked in 4lo . and then had to get the computer replaced $$$$ . I also had an acuator replaced aswell . ($100) try disconecting the battery for 20-30mins . sometimes that resets things enough . Good luck . and sometimes it is good to get 2 or 3 opinions from other mechanics .

BobbleSmitty · Post by **BobbleSmitty** » Thu Oct 06, 2005 12:41 pm

I got my truck back today. The write up says, "Replaced transer case control module." QTY - 1, FP Number - 15741322, Description - MDLASM 4.563... I don't really know what any of that is or what they actually did, but it does work now as it should. Anyone else have a problem with their transer case control modules??

Post by **HenryJ** » Thu Oct 06, 2005 2:47 pm

Transfer Case Shift Control Module

BobbleSmitty · Post by **BobbleSmitty** » Thu Oct 06, 2005 2:56 pm

Good thing mine was covered under warranty! That cost is pretty steep!

BobbleSmitty · Post by **BobbleSmitty** » Wed Nov 09, 2005 7:38 pm

Well, just about a month has passed and I haven't used the 4wd since I had it fixed in October. I tried it today and whataya know, it will not shift into 4hi. If I stop and put it in neutral, it will shift to 4Lo, but will not shift into 4hi. I tried it all, shift on the fly, in park, in drive at a stop, in neutral at a stop, neutral while rolling a little... Nothing! I am dropping it off tomorrow morning at the dealership. I'm thankful that this is happening before old man winter sets in here in the snow belt because I would not want to be stuck with out the 4x4. I'll see what happens tomorrow. Any suggestions on what I should mention to the service manager on why it didn't work the first time they fixed, maybe something else causing it??? Lemme know what you guys think.

Thanks,

-Bob

Post by **HenryJ** » Wed Nov 09, 2005 7:49 pm

Any lights or codes?

How about a new switch?

Sorry, I'm fish'n here.

BobbleSmitty · Post by **BobbleSmitty** » Wed Nov 09, 2005 7:50 pm

Nothing out of the ordinary... when i push the 4hi button in neutral, both 4hi and 4lo blink a few times then goes back to 2wd. If I hit 4hi while driving in 2wd nothing happens at all.

Post by **HenryJ** » Wed Nov 09, 2005 8:01 pm

I am not sure how much of this may apply-

gmshades wrote: Electronic 4x4

What is wrong, How to fix, How to install

***HOW TO CHECK WHAT IS WRONG***

You will probably know when your 4x4 has failed when you needed it in the mud pit. Mine, for instance, failed by not doing anything when I hit the 4HI button. However, it would go into 4LO.

To read the codes for the 4x4 with electric shift transfer case, install a jumper wire from terminals "J" and "A" on the ALDL (12 pin connector under the driver's side dash)

The lights on the 4x4 indicator (switch) will flash in a pattern, there are only 4 codes, one flash is code one, 2 flashes is a code 2, and so on...

Code "1" is "RAM standby power" and is considered normal, may be caused by clearing the codes.
Code "2" is "Encoder fault"
Code "3" is "TCCM motor circuit"
Code "4" is "RAM/ROM failure"

If you have the codes 2 or 3 check all the encoder motor connections at the transfer case, if OK it will need a new encoder motor assembly.
If you have code 4, replace the TCCM.

Make sure all connections are good and no corrosion, and then it's either an encoder or TCCM.

***TO FIX THE TCCM***

The TCCM is located behind the glove box, and is accessed from underneath the dash. To remove, the kick panel and black cover come off. Then a 1/4" screw holds the "brains" in the dash. The middle computer is the Truck's brain, the one on the backside is the TCCM, and on the front is the small ABS computer. Simply loosen the 2 10mm nuts on each side, and they will separate.

***WAYS TO FIX THE ENCODER MOTOR PROBLEM.***

This is the most common problem, and was my problem.

Cheap way - To clear the codes and reset the computer, pull the 5 amp TCCM fuse, located at the bottom of the fuse box. Wait at least a half hour, and then replace the fuse. Turn the ignition key to run, wait for the 4x4 lights to blink, and then turn off. Repeat 5 times, and then start the truck.

Decent price way - I just went and bought a rebuilt encoder motor from a company off of Ebay. Their company is http://www.northernautoparts.com The part cost me around $140 with a 1 year warranty and $38 core refund when I send the old one back.

Expensive way - buy a brand new one from GM for over $300.

***HOW TO INSTALL THE NEW ENCODER MOTOR***

Lucky way - Only thing that needs to be removed is the encoder motor itself. Tools needed are a 10mm hand wrench and a 8mm and 10mm socket wrench. The 10mm socket will work on the upper and lower bolts, while the regular wrench is needed for the middle bolt. (Tight squeeze). The 8mm socket is for the electric plug.
Then, just pull out, and wiggle it out of the truck. Install in reverse order.

Unlucky way - This means the encoder motor did not just wiggle out. Now the front drive shaft will have to be removed at the transfer case. Then, a yolk puller is needed in order to remove the yolk from the transfer case. Once this is done, go to the directions in lucky way.

Writeup by gmshades

Resetting may help.

BobbleSmitty · Post by **BobbleSmitty** » Wed Nov 09, 2005 8:07 pm

Thanks

Kinda the same problem as me, 4Lo works but no 4Hi... I dont have a jumper wire and I really haven't a clue what that is, so I will take it up tomorrow and see what they do. With that information, I now know that there can be a few reasons why this is happening and what they may be so I don't feel dumb when questioning the service manager. Thanks alot

-Bob

killian96ss · Post by **killian96ss** » Thu Nov 10, 2005 9:06 am

The way you describe what's happening it sounds like the encoder motor. My CC was doing the same exact thing a few months back and when the dealer raplaced the encoder motor everything worked fine again.

This isn't the first time this has happened to me as I am now on my third encoder motor.

Steve

BobbleSmitty · Post by **BobbleSmitty** » Thu Nov 10, 2005 2:35 pm

Well, I got my truck back and the 4x4 works again. The printout is exactly the same as the last one. They replaced the Transfer Case Control Module. That's what they had done last month, I didn't use the 4x4 at all after the first day to see if it worked. So I'm gonna keep an eye on this each week to see if the 4x4 continues to work. If not, I would assume that the 4 wheel drive being a really big factor for a truck, this would be the 3rd time that this has happened and I will consider the lemon law. I hope it doesn't lead to that, but after my warranty is up, I dont want to be stuck with paying to have my truck fixed every month. We'll see how it all goes!

-Bob

BobbleSmitty · Post by **BobbleSmitty** » Fri Nov 25, 2005 9:08 am

Exactly two weeks after having the 4x4 fixed, what's it do?? It stops working in the middle of a blizzard on the highway!!! I'm getting really tired of having to take my truck in every two weeks to get it fixed. I demanded that they give me a crewcab pickup truck with 4x4. As much as they didn't want to, I got my way. They gave me a Colorado. But I am getting extremely frustrated with this issue.

doughboy5499 · Post by **doughboy5499** » Fri Nov 25, 2005 12:00 pm

I am having the same problem with my '01 sonoma. I have had to unhook the battery, to let things reset, twice now in the last month. I realize this is just a quick fix. So i keep a ratchet in the truck incase it goes out on my way to work. Unplug it at work so i have it on th e way home. Gonna be a long winter if this keeps up.

killian96ss · Post by **killian96ss** » Fri Nov 25, 2005 12:34 pm

BobbleSmitty, I'm pretty sure it's the Encoder Motor. Don't let them just keep replacing the T-case control module as it doesn't seem to be your problem. Tell them to check the Encoder Motor, or take your truck somewhere else.

Steve

S10CREW01 · Post by **S10CREW01** » Fri Nov 25, 2005 4:05 pm

Thanks for all the good info:

HenryJ wrote:I am not sure how much of this may apply-

gmshades wrote: Electronic 4x4

What is wrong, How to fix, How to install

***HOW TO CHECK WHAT IS WRONG***

You will probably know when your 4x4 has failed when you needed it in the mud pit. Mine, for instance, failed by not doing anything when I hit the 4HI button. However, it would go into 4LO.

To read the codes for the 4x4 with electric shift transfer case, install a jumper wire from terminals "J" and "A" on the ALDL (12 pin connector under the driver's side dash)

The lights on the 4x4 indicator (switch) will flash in a pattern, there are only 4 codes, one flash is code one, 2 flashes is a code 2, and so on...

Code "1" is "RAM standby power" and is considered normal, may be caused by clearing the codes.
Code "2" is "Encoder fault"
Code "3" is "TCCM motor circuit"
Code "4" is "RAM/ROM failure"

If you have the codes 2 or 3 check all the encoder motor connections at the transfer case, if OK it will need a new encoder motor assembly.
If you have code 4, replace the TCCM.

Make sure all connections are good and no corrosion, and then it's either an encoder or TCCM.

***TO FIX THE TCCM***

The TCCM is located behind the glove box, and is accessed from underneath the dash. To remove, the kick panel and black cover come off. Then a 1/4" screw holds the "brains" in the dash. The middle computer is the Truck's brain, the one on the backside is the TCCM, and on the front is the small ABS computer. Simply loosen the 2 10mm nuts on each side, and they will separate.

***WAYS TO FIX THE ENCODER MOTOR PROBLEM.***

This is the most common problem, and was my problem.

Cheap way - To clear the codes and reset the computer, pull the 5 amp TCCM fuse, located at the bottom of the fuse box. Wait at least a half hour, and then replace the fuse. Turn the ignition key to run, wait for the 4x4 lights to blink, and then turn off. Repeat 5 times, and then start the truck.

Decent price way - I just went and bought a rebuilt encoder motor from a company off of Ebay. Their company is http://www.northernautoparts.com The part cost me around $140 with a 1 year warranty and $38 core refund when I send the old one back.

Expensive way - buy a brand new one from GM for over $300.

***HOW TO INSTALL THE NEW ENCODER MOTOR***

Lucky way - Only thing that needs to be removed is the encoder motor itself. Tools needed are a 10mm hand wrench and a 8mm and 10mm socket wrench. The 10mm socket will work on the upper and lower bolts, while the regular wrench is needed for the middle bolt. (Tight squeeze). The 8mm socket is for the electric plug.
Then, just pull out, and wiggle it out of the truck. Install in reverse order.

Unlucky way - This means the encoder motor did not just wiggle out. Now the front drive shaft will have to be removed at the transfer case. Then, a yolk puller is needed in order to remove the yolk from the transfer case. Once this is done, go to the directions in lucky way.

Writeup by gmshades
Resetting may help.

BobbleSmitty · Post by **BobbleSmitty** » Fri Nov 25, 2005 6:33 pm

I got my truck back around 5:00pm... This time they replaced the encoder motor. It seems to be working for now I guess. We'll see how long it stays working!!

Post by **HenryJ** » Fri Nov 25, 2005 6:55 pm

All that is left is to replace the switch. That '99 Tahoe I have in the fleet needed the TCM first and then a few weeks later I had to replace the switch. It has been doing good now for a few months.

killian96ss · Post by **killian96ss** » Fri Nov 25, 2005 7:41 pm

BobbleSmitty wrote:I got my truck back around 5:00pm... This time they replaced the encoder motor. It seems to be working for now I guess. We'll see how long it stays working!!

Glad to hear they finally replaced the right part.

I'm on my 3rd encoder motor.

With such a high failure rate on this part, I'm surprised GM hasn't done something to correct the problem.

Steve

doughboy5499 · Post by **doughboy5499** » Sat Nov 26, 2005 4:59 am

Does anyone have a GM part number for this Encoder Motor? I think I might look up on E-Bay to find a rebuilt one too. Since I do not have warranty on mine.

BobbleSmitty · Post by **BobbleSmitty** » Sat Nov 26, 2005 7:09 am

On my invoice from the dealership the number is 15636696.

Post by **HenryJ** » Sat Nov 26, 2005 7:15 am

That looks like the right one:

GM PART # 15636696
CATEGORY: All
PACK QTY: 1 CORE CHARGE: $0.00
GM LIST: $512.05
OUR PRICE: $291.87
DESCRIPTION: MOTOR,TRF

jeff024 · Post by **jeff024** » Sun Nov 27, 2005 2:37 am

heres a switch on ebay
SWITCH

$21.00 shipped for $4.00

BobbleSmitty · Post by **BobbleSmitty** » Fri Dec 02, 2005 7:57 pm

Well, the 4x4 seems to be back to normal now!! I'm having no problems at all since they replaced the encoder motor. We got nearly 20 inches of snow and some really large drifts (3 feet +). I had plenty of fun today!! It worked just as it should when ever I pushed the button!!

doughboy5499 · Post by **doughboy5499** » Wed Sep 27, 2006 7:12 am

ENCODER MOTOR

I was wondering if an encoder motor like this one I found on E-Bay would be a ggod enough one to buy for our truck? It says it is new and it is alot cheaper than through the Dealer.

doughboy5499 · Post by **doughboy5499** » Tue Nov 28, 2006 8:16 am

Where exactly is the encoder motor located. Any pics anywhere that could be used as a reference. I think I am going to replace mine with a rebuilt one after the begining of the year.

F9K9 · Post by **F9K9** » Tue Nov 28, 2006 8:46 am

The Front drive shaft sits along where you see the bolts being removed. It's on the driver's side.

GeorgesBlazah · Post by **GeorgesBlazah** » Tue Nov 28, 2006 9:02 am

I have a pushbuttom 4x4 switch if anyone is looking to replace theirs. It works, jus tthe 4hi, 2hi and 4lo lights dont light up, but the amber indicators work. Sorry to hijack.

I havent had any problems with my 4x4.

*knock on wood*

doughboy5499 · Post by **doughboy5499** » Wed Nov 29, 2006 2:14 pm

S10CREW01 wrote:Thanks for all the good info:

HenryJ wrote:I am not sure how much of this may apply-

gmshades wrote: ***WAYS TO FIX THE ENCODER MOTOR PROBLEM.***

This is the most common problem, and was my problem.

Cheap way - To clear the codes and reset the computer, pull the 5 amp TCCM fuse, located at the bottom of the fuse box. Wait at least a half hour, and then replace the fuse. Turn the ignition key to run, wait for the 4x4 lights to blink, and then turn off. Repeat 5 times, and then start the truck.

Writeup by gmshades
Resetting may help.

What fuse is this? In the fuse box under the hood I don't have one labeled "TCCM". Is it just the "transfercase ( 4x4 )" fuse? If so then this fuse is a 20 amp fuse not 5. Am I in the right location? If I could figure this out it would be easier than having to unhook the battery cables (easy fix for now ) every time I know I am going to need to use/need the 4wd.

F9K9 · Post by **F9K9** » Wed Nov 29, 2006 3:04 pm

I just learned another valuable lesson

rlrnr53 · Post by **rlrnr53** » Wed Nov 29, 2006 4:06 pm

Another way that has worked for me, is to pull the courtesy light fuse for a couple of hours. I don't know how this works, but it seems to reset the BCM. After the first time that I i did this when my dome light wouldn't go out,I was surprised to find out that my transfer case shifted normally, and the problems with my Retained Accessory Power was cured.

Post by **HenryJ** » Wed Nov 29, 2006 4:12 pm

doughboy5499 wrote:
HenryJ wrote:I am not sure how much of this may apply-
gmshades wrote:... To clear the codes and reset the computer, pull the 5 amp TCCM fuse...
Resetting may help.
What fuse is this? In the fuse box under the hood I don't have one labeled "TCCM". Is it just the "transfercase ( 4x4 )" fuse? If so then this fuse is a 20 amp fuse not 5. Am I in the right location?

The 4wd fuse would make sense, I guess. There may be others as well? ECM B?

I really haven't looked into which would be the newer equivalents of the older TCCM.

Most often I just suggest removal of the battery cables.