4x4 Not working AGAIN

2006Envoy

Newbie
Hello all,

I just found this site after reading through multiple threads at the trailvoy site and I know this subject here and over there has been beaten to death in problems and solutions but I cannot find any definitive answers for my exact problem. Here's a bit of history about the issue:

I got the vehicle about 18 months ago and I now have my 4th bad Encoder Motor.

1st (Within the first 2 months of having the vehicle): The fist one shorted out when shifting out of 4x4 during a snow storm but my front diff never disengaged and that's when I knew I had an issue. I got a junkyard motor and confirmed the old one was bad. About 1 month after the motor had died.

2nd (Same time frame): The junkyard one, while installing, shorted out per the mechanic that installed the 3rd one.

3rd (At the beginning of the 2017/18 winter): Used it maybe once or twice before and then that one shorted out. Mechanic said he fixed the short and it should be fine. Now on the 4th one roughly 8 months later

4th (Used multiple times since it was installed in mud, deep ponding on roads and other mild terrain): This one lasted for quite some time until about 2 weeks ago when I needed it for something besides going off road and snow and it failed AGAIN on me.

I've tried doing the "go to fix" by disconnecting the battery for 30 minutes and pulling fuse 8 from the front fuse box and 48 from the rear. Nothing improved, I am still in Auto 4x4. The only noises I hear when trying to sift to any other configuration is the relays. I'm not sure if this could be a coincidence or not but the day prior to this Encoder failing I replaced both my front hubs with MOOGs. Also other ongoing issues would be a P1682 code which when it trips it turns my 4x4 maintenance light on and turns my tractiong control off. And lastly the Encoder always seems to fail in the cold New England weather.

Any input from anyone else who has had the same or similar issue would be greatly appreciated. I am beyond frustrated and I cannot seem to trace this issue and I am tired of throwing money at the same part over and over again.
 

Mooseman

Master Blaster
Moderator
Any of these were NEW or REBUILT? Anything from a junker is a roll of the dice unless the truck looks like it was scrapped with a visibly new encoder motor on it.

Of the choices I see on RA:
Cardone: rebuilt with questionable durability
ACDelco: rebuilt by OEM so would be best available
Dorman: New however their track record with anything electrical is questionable

On eBay, I saw an APDTY 711015 (New) but I don't know anything about this brand.
 

2006Envoy

Newbie
Thread Starter
The first one I believe was the original from when the vehicle was built, the second I grab from a salvage yard and shorted that out. The third one was done by a transmission specialist along with the 4th one, the one that just died. To the best of my knowledge he installed new ones and fixed the shorts in the wiring harness. My last guess is it could be a TCCM issue that could be causing even though it's not a 2002.
 

MRRSM

Lifetime VIP Supporter
With all of those changes in the Transfer Case Hardware… Did you have the opportunity to get all of the Older PCM-TCCM Software Updated via a Dealership Tech 2 to TISWEB Update? This very well could be a Software Issue ...rather than anything Mechanical. Even though this next idea involved the 2002-2004 Tbs/Envoys… Bear with me for just a moment…

FWIW... While THIS TSB Data is for OTHER TCCM problems… it will give you an idea that some things can go wrong with the same Databus Module Equipment in your later model SUV and perhaps suggest that you get with a friend who has either a Tech 2 or a comparable device for accessing the PCM and related TCCM Module(s) via the TIS2000 and/or the ACDelco Online TIS2WEB Service to perform the Latest SW Updates next ...and see if THAT turns out to be the actual issue:

Delayed Engagement of Front Wheels During a Slip Condition (Reprogram
Transfer Case Control Module (TCCM)) #04-04-21-001 - (May 14, 2004)
Delayed Engagement of Front Wheels During a Slip Condition (Reprogram
Transfer Case Control Module (TCCM))
2004 Buick Rainier


2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT

2002-2004 GMC Envoy, Envoy XL

2004 GMC Envoy XUV

2002-2004 Oldsmobile Bravada

with New Venture Gear (NVG) 126 (RPO NP4) or NVG 226 (RPO NP8) Transfer Case

Condition
Some customers may comment on a hesitation or delayed engagement of the
front wheels during a slip condition.


This condition may manifest itself in the normal AWD mode for the Bravada
and Rainier models, and in the Auto 4WD mode for the TrailBlazer and Envoy
models.


Correction
Reprogram the Transfer Case Control Module (TCCM) using normal SPS
procedures using TIS software version 11.5 released November 10th, 2003 or
newer. Refer to Transfer Case Control Module Reprogramming for additional
information.


2002 vehicles will require the replacement of the transfer case control
module prior to reprogramming.


Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System (Reprogram Transfer
Case Control Module Using Labor Operation Code N8521) #02-04-21-006D - (Mar
24, 2004)
Inoperative 4WD/AWD Lamps, Inoperative 4WD/AWD System (Reprogram Transfer
Case Control Module Using Labor Operation Code N8521)


2004 Buick Rainier

2002-2004 Chevrolet TrailBlazer, TrailBlazer EXT

2003-2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe

2002-2004 GMC Envoy, Envoy XL

2003-2004 GMC Sierra, Yukon, Yukon XL

2004 GMC Envoy XUV

2002-2004 Oldsmobile Bravada

with Electronic Shift or Active Transfer Case (RPOs NP1, NP4 or NP8)

This bulletin is being revised to add information to Step 5 of the
procedure. Please discard Corporate Bulletin Number 02-04-21-006C (Section
04 -- Driveline/Axle).


Condition
Some customers may comment that the 4WD/AWD indicator lights on the selector
switch do not work, or the 4WD/AWD system may be inoperative and/or the
service 4WD light is illuminated. The condition is typically intermittent
and always occurs at key-up.


Cause
The Transfer Case Control Module (TCCM) has not received the wake-up call
during key-up and has remained in the "sleep mode".


When the TCCM is in the "sleep mode", it will not communicate with the class
II bus or the Tech 2®.


Correction
1.. Try to communicate with the TCCM. If no communication, go to step 2.
If communication is possible, go to step 5.
2.. Remove the underhood (ATCM or TREC) TCCM fuse.
3.. Wait 30 seconds.
4.. Reinstall the fuse. The module should "wake up" and communicate with
the Tech 2®.
5.. Check for codes in the TCCM. If a C0550 is found current or in history
with or without other codes, replace the module and go to step 6.
6.. Reprogram the TCCM using normal SPS procedures, using TIS software
version 3 released March 8th, 2004 or newer.
7.. Verify operation and that no codes are present.
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300
and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM))
#03-04-21-005 - (Jun 5, 2003)
Service 4WD Light On, 4WD Inoperative, Diagnostic Trouble Codes (DTC) C0300
and/or C0305 Set (Reprogram Transfer Case Control Module (TCCM))
2003 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer


2003 GMC Envoy, Sierra, Yukon, Yukon XL

2003 Oldsmobile Bravada

with 4WD (RPOs NP4, NP8)

Condition
Some customers may comment that the Service 4WD light is on and/or the 4WD
is inoperative.


Cause
Condition may be caused by a TCCM calibration issue.


Correction
Follow the service procedure below for diagnosis and repair of this
condition.


1.. With a scan tool, select the TCCM DTCs.
a.. If TCCM DTCs C0300 or C0305 are present in the TCCM, continue with
TCCM reprogramming in Step 2.
b.. If TCCM DTC C0374 is present with any of the above codes, disregard
and clear the DTC and continue with TCCM reprogramming in step 2.
c.. If TCCM DTC C0374 is present alone with none of the above listed
codes, additional diagnosis is required. Refer to Service Information (SI)
for proper diagnosis of the applicable vehicle.
d.. If TCCM DTC C0550 is present, refer to DTC C0550 in SI for proper
diagnosis of the applicable vehicle.
2.. Clear all DTCs and reprogram the TCCM with TIS version 3.5 or newer
released to the dealers on 3-22-03. Refer to Transfer Case Control Module
Reprogramming (SI Document ID #727487).
Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow
Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and
Reprogram TCCM) #02-04-21-008A - (Feb 13, 2003)
Shudder, Rocking Motion, Binding, Feels Like Vehicle is Stuck in 4WD (Crow
Hop) When Turning at Low Speeds (Replace Transfer Case Encoder Sensor and
Reprogram TCCM)
2002-2003 Chevrolet TrailBlazer


2002-2003 GMC Envoy

2002-2003 Oldsmobile Bravada

This bulletin is being revised to update the service procedure and
incorporate the fluid exchange. Please discard Corporate Bulletin Number
02-04-21-008 (Section 04 -- Driveline Axle).


Condition
Some customers may comment that when turning, the vehicle feels like it is
binding, or the vehicle feels like it is stuck in 4WD (crow hop), or that
the 4WD system is not working correctly. A shudder type sensation is felt.


Technician Diagnosis
This intermittent condition may be difficult to duplicate. The potential is
there at all times for the Bravada. The potential is only present in the
Auto Mode of the transfer case with the TrailBlazer or Envoy.


Correction

Important
It is extremely important to check all of the tires before repairs are
attempted for these types of customer concerns. Mismatched tires may cause
these type of customer concerns. Inspect the tires in the following areas:


a.. Ensure that the tires are inflated to the recommended tire pressure as
listed on the tire placard on the driver's door.
b.. Use a tire tread depth gauge to determine the tread depth. The tire
tread depth must be nearly equal on all four corners of the vehicle.
c.. Ensure that the tires are all the same brand, size, and tread design.



Important
Pay particular attention so that the proper parts are replaced. The parts
terminology is somewhat confusing. You will be replacing the encoder
(sensor) and gasket not the complete motor assembly.


Currently, the General Motors Parts Catalog lists the following names:

a.. Motor Asm, Trfer Case Encoder (This is the Encoder (Sensor). It looks
like a donut with three (3) contacts on one side).
b.. Gasket.
c.. Actuator Asm, Trfer Case Four Whl Drv (This is the complete motor
assembly consisting of the Motor and housing, the Motor Asm, the Trfer Case
Encoder (Sensor), and the gasket).


Use the following procedure to replace the Motor Asm, Trfer Case Encoder
(Sensor) and Gasket.
 

Mooseman

Master Blaster
Moderator
Maybe there's a problem with the shop rebuilding them? Just sayin'.

I doubt very much it's a TCCM issue. You could try replacing it with one from a 2003+. Have you tried taking the encoder motor out plugged in and watching to see if it works while you move the switch? If it's working correctly, it could be the transfer case. Have you tried moving the shaft in the transfer case gently with pliers? When was the last time the fluid was replaced? It has a relatively short 50k mile interval. Not replacing it does cause failures.

I've had one seize on me in my '02 and replaced it with one from a junker. It looked fairly new so it lasted till I scrapped it. In my Saab, that one also seized and I took it apart. The gears inside were broken. That one I bought a rebuilt Cardone (only one available locally).

They usually don't "short". They usually fail mechanically or seize up due to water infiltration. A short would cause the fuse to blow.

Re-reading you initial post, you say you don't hear anything when you move the switch. You should hear the front disconnect move when you put it in A4WD and/or 4HI. This could mean it's actually your disconnect is not working. Please look at this to completely troubleshoot your system.
4WD not working? Step inside.
 

2006Envoy

Newbie
Thread Starter
When was the last time the fluid was replaced? It has a relatively short 50k mile interval. Not replacing it does cause failures.

That I could not tell you. I got the Envoy with 14x,xxx miles on it and I'm roughly 179,000. I wanted to replace those fluids but the cold came quickly and extremely harsh. I may try to do those today since it's a relatively nice day.

They usually don't "short". They usually fail mechanically or seize up due to water infiltration. A short would cause the fuse to blow.

That is what the mechanic had told me the first time when he fixed it which I believe was the issue when the 2nd one went because 4x4 service light, traction control "Off" light, and traction control maintenance light was on.

Re-reading you initial post, you say you don't hear anything when you move the switch. You should hear the front disconnect move when you put it in A4WD and/or 4HI. This could mean it's actually your disconnect is not working.

All 4 times when the motor has died the front actuator will not function. When it first happened I was "stuck" in 4x4 but the front actuator did not disengage the front diff but the transfer case was in 2HI. Every time I would try to shift out of 4x4 the encoder would try but could not. I pulled it off and you can hear it trying to move but very weak. When I plugged a new motor in the gear spun and had a very different noise to it as well.

Right now when I try to shift into a different configuration my voltage will drop meaning that it is sending power to the encoder but the encoder is struggling and cannot move. Same symptoms as my first, second, and third failed encoder motor.

http://gmtnation.com/forums/threads/4wd-not-working-step-inside.106/

I have looked into this both here and at TrailVoy and I could never find a solution where the problem was what I have stated.

I have a GM shop looking at it completely 12/21 but I was still hoping I could have some sort of answer on why this keeps happening and why it seems to only happen in the cold but after the drive train had been warmed up meaning there really is no resistance in the fluids.
 

Reprise

Lifetime VIP Supporter
After reading through this post, I'm starting to think 'resistance' of a different kind - electrical.

Just a WAG on my part, but I'm thinking something in that area is damaging the motors (continuous / low load - ?) I'm not an EE or an ASE tech, so my guess may not be worth the electrons it took to type it.

To have that many 'fail' due to bad luck alone - you probably have better odds of being hit by a lightning strike.
 

Mooseman

Master Blaster
Moderator

2006Envoy

Newbie
Thread Starter
Update on my 4x4 issue. I just got back from the GM shop and the final diagnosis on the issue was a bad TCCM. The TCCM what shorting which in turn was causing the Encoder Motor to internally short out causing the 4x4 to cease to work. The mechanic had traced all the wiring which he confirmed there was no bare wiring causing the shorting.

When he checked the TCCM he had seen residue from it shorting out. I dismantled the TCCM and I could not see any issues on the inside but that doesn't mean that there is a chip on the board that is bad or an internal short in the board.

Final resolution will be to replace the TCCM just to insure that the problem will not be continued and obviously the shorted out Encoder Motor.

Thank you all for you help, opinions, and other various information on what could have gone wrong.
 

MRRSM

Lifetime VIP Supporter
This is a Brilliant (additive) COMPLETE Diagnostic Video on a 4WD Non-Shifting Issue focusing here on the C0305 Code as being caused by a DAMAGED VSS Unit. The VOP (Video Original Poster) uses a combination of Scanner Diagnostics, Power Probe, DMM and his PICO-Scope as well as the Hands-On R&R imagery with a follow on Component Autopsy and Real World Testing to Isolate and VERIFY the Problem before settling on the Repair Action. The MOST important aspect of this memorialized work is just how THOROUGH the VOP is when doing the Job:

 
Last edited:

azswiss

Registered Member
"Even the parts changers of the world would have, by luck, come to the right diagnosis in this case, but where's the fun it that?" Precisely!
 

Forum Statistics

Threads
21,616
Messages
614,953
Members
15,724
Latest member
Sam_Augusta_Ga

Members Online

Top Bottom