2003 Yukon..4wd Dilemma. Help!

[TooTurntDad]

I traded a VW Passat for a 2003 Yukon I have. Its a bit of a long story but thats for a rainy day.

So, after seller dishonesty and my error of not being more... “****” about inspecting the truck until I took it... Im left with... A lemon.

So, heres whats going on:

When I got on the highway I figured the truck could do highway speeds. Nope, not at all. Anything over 65; brake light goes on, abs light trips, speedometer goes crazy, kicks out of OD and goes into a lower gear, then neutrals itself out before going back into OD again once under 65mph.

I get home finally (5.5hrs later) and look around it in my garage with much better lighting. My guesses to my problem were a bad transfer case speed sensor and bad wheel speed sensors. So I replace them; do a test drive and the problem didnt get fixed. So I figured, “hmm lets try something else” so I go and see if its 4wd related. I basically find out my push button doesnt work. Itll light up before the Yukon is officially started but thats it.

I got to tinkering with it some today and found that the previous owner took out the front driveshaft. I had the rear end lifted, turned the truck on, and seen that the the transfer case was spinning which lead me to believe that Im stuck in 4Hi. I tried to manually do it by removing the motor and taking a pair of channel locks and turn it counter clockwise two clicks (my guess) and hope it kicked it out of 4wd. Took it for a test drive and found myself with little to no power. Went back in and put it back to its original position and decided to ask questions before I end up breaking something.



So, do these 4wd systems require a front driveshaft because I have access to one from a parts truck local, but I feel it still wouldnt resolve my service 4wd light and Id get power to the front wheels and potentially blow the front driveshaft out.

I do notice vibration from the transfer case when going highway speeds.

So this is the list of things I have done in relation to the matter:

-Replace front wheel speed sensors
-Replace transfer case speed sensor
-Replace push button 4wd switch
-Ohm out and checked voltage to actuator and transfer case motor
-Tried manually switching to 2wd
-Tried to use a vampire clip to a positive wire in the 4wd switch to give power to the switch
-Replaced the fuse for the 4wd system.


The only thing left that I could think of that I’ll get around to on my day off is checking the TCCM and pray and hope thats the culprit which I have access to a spare one from a parts truck.

But anywho, sorry for the long and drawnout post. Im just giving every detail of what is going on. Hopefully its in the right section. Hopefully with some guidance from you guys I can get this fixed and hopefully this post can help others in the future.

 

[Fless]

Welcome to TYF! Post up some pics when you get a chance.

I'd recommend getting a bidirectional scanner on it (preferably a Tech 2, if you can get your hands on one) to check out the transfer case electronics and drivetrain status. If you have a DIC (Driver Info Center) does it show "Service 4wd System?" Gotta get those codes to know what's going on.

There is a critical ground underneath the driver's door, right behind the LF wheel near the frame rail. Two bolts there should be holding three ground wires; one of those can affect the 4x4 system. Clean and tighten those grounds. Wire connections for #2, 3 & 4 on the diagram:

On the dash switch connector there should be a constant 5v from the TCCM; be sure to check it with the ground in the connector to be sure both circuits are good. I can look for the pinout if you need one. I see that you changed the switch, but do you know if the button resistance values are within spec? Need a digital ohm meter for that; let me know if you need the ohm values.

Replacing the TCCM with the spare may not work since the OE modules are programmed to the truck. If it's a Dorman replacement programming is not needed.

I would recommend NOT trying to switch the modes on the encoder motor since doing that can move the actuator to a non-neutral position and it can be difficult to get it back.

 

[TooTurntDad]

Welcome to TYF! Post up some pics when you get a chance.

I'd recommend getting a bidirectional scanner on it (preferably a Tech 2, if you can get your hands on one) to check out the transfer case electronics and drivetrain status. If you have a DIC (Driver Info Center) does it show "Service 4wd System?" Gotta get those codes to know what's going on.

There is a critical ground underneath the driver's door, right behind the LF wheel near the frame rail. Two bolts there should be holding three ground wires; one of those can affect the 4x4 system. Clean and tighten those grounds. Wire connections for #2, 3 & 4 on the diagram:

View attachment 262394

On the dash switch connector there should be a constant 5v from the TCCM; be sure to check it with the ground in the connector to be sure both circuits are good. I can look for the pinout if you need one. I see that you changed the switch, but do you know if the button resistance values are within spec? Need a digital ohm meter for that; let me know if you need the ohm values.

Replacing the TCCM with the spare may not work since the OE modules are programmed to the truck. If it's a Dorman replacement programming is not needed.

I would recommend NOT trying to switch the modes on the encoder motor since doing that can move the actuator to a non-neutral position and it can be difficult to get it back.

Great info! I’ll get pictures up as soon as I can. As for the grounds underneath the drivers door, I forgot to mention that I did clean them up and get back to bare metal again for better contact. Still no luck.

I dont remember the ohm values in the switch off the top of my head but based on a YouTube video that I used to go through some of the steps I took; the read out was suppose to be .9 something and I had similar results. Would love to have that info again passed along.

My DIC does show “Sevice 4wd System” I dont have access to a scanner but Im sure a tech at a dealership can help.

I also found out my 2a fuse for my steering wheel controls is out and half my radio harness is missing because the PO didnt use the interface to install the aftermarket radio, which lead me to believe I needed a whole new body harness (which I painstakenly got after pulling it myself)

This is a first time experience for me on these trucks. Ive had an 06 XL with no issues and an 02 Tahoe with no issues either. Kinda kicking myself in the ass for even letting both of them go now that Im dealing with this.

But, nonetheless once its fixed I’ll be absolutely thrilled.

Also, if you dont mind, if you have any good links to wiring diagrams etc please share them. The more I know the merrier.

 

[Fless]

Switch testing... here’s a link with info on how to test the dash switch. Post #10.
https://www.tahoeyukonforum.com/threads/03-4x4-issues.112093/

This guy shows how to check them all, but his presentation isn't all that great. LOL He states one of the values wrong but I don't recall which one; see the Atraonline article link below.
https://youtu.be/JNWxhIWs8Uk starting at about 2:10

This thread might also help: https://www.tahoeyukonforum.com/threads/4x4-selector-going-to-n-selection-not-working.120624/

And this guy has some diagnostic info with the actual switch position ohm values. (My '04 wiring wasn't exactly the same for the ATCM, but the switch ohm values are correct. Apply those to the You Tube video. My ATCM voltage to the switch is 5v; yours will be, too, I think.)
Atraonline article: https://atracom.blob.core.windows.net/gears/2006/2006-08/2006_08_08.pdf

Also, here's Pete Huscher's article describing how the Tcase works:
https://atracom.blob.core.windows.net/gears/2006/2006-07/2006_07_10.pdf

EDIT: maybe let us know what part of the country you're in; sometimes there's a helpful forum member nearby with a Tech 2 or other suggestions.

 

[TooTurntDad]

Switch testing... here’s a link with info on how to test the dash switch. Post #10.
https://www.tahoeyukonforum.com/threads/03-4x4-issues.112093/

This guy shows how to check them all, but his presentation isn't all that great. LOL He states one of the values wrong but I don't recall which one; see the Atraonline article link below.
https://youtu.be/JNWxhIWs8Uk starting at about 2:10

This thread might also help: https://www.tahoeyukonforum.com/threads/4x4-selector-going-to-n-selection-not-working.120624/

And this guy has some diagnostic info with the actual switch position ohm values. (My '04 wiring wasn't exactly the same for the ATCM, but the switch ohm values are correct. Apply those to the You Tube video)
Atraonline article: https://atracom.blob.core.windows.net/gears/2006/2006-08/2006_08_08.pdf

Also, here's Pete Huscher's article describing how the Tcase works:
https://atracom.blob.core.windows.net/gears/2006/2006-07/2006_07_10.pdf

EDIT: maybe let us know what part of the country you're in; sometimes there's a helpful forum member nearby with a Tech 2 or other suggestions.

Sweet! I’ll get to reading.

And to answer your question about my location. Im in Knoxville, TN.

 

[Fless]

Ok, good. The diag article says that the connectors and wiring diagram shown are from a 2001 Silverado. I'd be curious if your ATCM voltage to the dash switch is 8v or 5v.

 

[JonnyTahoe]

You never noticed the front driveshaft was missing. You never test drove the truck?

 

[Fless]

You never noticed the front driveshaft was missing. That would of been red flag number one. You never test drove the truck?

Man, kick a guy while he's down!

 

[Joseph Garcia]

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics, please.


I see that @Fless had already responded, and is giving you sage advice. Other members of this Forum will chime in to further assist you, if needed.

 

[Doubeleive]

You never noticed the front driveshaft was missing. That would of been red flag number one. You never test drove the truck?

Right? especially on a trade o'well once he get's it straightened out it's probably the better end of the deal.

 

[TooTurntDad]

So things have been crazy at work.
Its peak season for FedEx with the holidays around the corner but I finally was able to get a code sheet made for this thing by the dealership near me.

The current codes are as follows:

B0026
B0043
B0164
B2722
C0225
C0321
C0327

P0332
P0420
P0430
(was able to grab these three codes from a basic scan prior to this)

P0741


I have a ton of others with history as well.

Not sure where to start. Sifting through good ole google to figure out the best approach.

So far what I have on its way and attempting to replace is:
-Brand new 4wd actuator
-Brand new 4wd transfer case motor
-TCCM which comes with yet, another 4wd switch.

Figured switching these out might put me a step foward into fixing this thing. Its just the other B and C codes I know nothing about.

Attached is the sheets they gave me feel free to give any input. Monday, I’ll be off and upload pics during the day to show what im working with. Just work has me swamped so its pretty rough at the moment lol.


As for those shocked at how I never noticed there was no front driveshaft, I did explain it was seller dishonesty and buyer error. Even had it on a lift to fix the exhaust and the exhaust guy and I never even batted an eye to it. It wasnt until I got under a few days later to mess with the actuator and found out lol.


Oh well. I have a new front driveshaft on standby but I dont think itd be best for me to install it just yet considering I daily drive this thing and I dont want to blow out my front diff and transfer case. Been there before when I couldnt get a work truck out of 4wd and destroyed an entire truck after the transfer case disintegrated. Oops.

Anywho Im done rambling for now.

 

[Tonyrodz]

So things have been crazy at work.
Its peak season for FedEx with the holidays around the corner but I finally was able to get a code sheet made for this thing by the dealership near me.

The current codes are as follows:

B0026
B0043
B0164
B2722
C0225
C0321
C0327

P0332
P0420
P0430
(was able to grab these three codes from a basic scan prior to this)

P0741


I have a ton of others with history as well.View attachment 262901View attachment 262902

Not sure where to start. Sifting through good ole google to figure out the best approach.

So far what I have on its way and attempting to replace is:
-Brand new 4wd actuator
-Brand new 4wd transfer case motor
-TCCM which comes with yet, another 4wd switch.

Figured switching these out might put me a step foward into fixing this thing. Its just the other B and C codes I know nothing about.

Attached is the sheets they gave me feel free to give any input. Monday, I’ll be off and upload pics during the day to show what im working with. Just work has me swamped so its pretty rough at the moment lol.


As for those shocked at how I never noticed there was no front driveshaft, I did explain it was seller dishonesty and buyer error. Even had it on a lift to fix the exhaust and the exhaust guy and I never even batted an eye to it. It wasnt until I got under a few days later to mess with the actuator and found out lol.


Oh well. I have a new front driveshaft on standby but I dont think itd be best for me to install it just yet considering I daily drive this thing and I dont want to blow out my front diff and transfer case. Been there before when I couldnt get a work truck out of 4wd and destroyed an entire truck after the transfer case disintegrated. Oops.

Anywho Im done rambling for now.

Did you return to the seller? Was it a dealer or private seller? I really hate that people do that to other people! I'm sure you work hard for your money. Just pisses me off!!

 

[TooTurntDad]

Did you return to the seller? Was it a dealer or private seller? I really hate that people do that to other people! I'm sure you work hard for your money. Just pisses me off!!

Private sale. Im not going back 3.5hrs. Just a hard learned lesson and moving forward. Like the truck, see the potential, just want to fix it even if its in stages. Progress is progress the way I see it

 

[TooTurntDad]

Heres a pic of the Yukon along with one of my Tahoe from a year ago. Not to get side tracked or off topic. End goal after everything is fixed is to respray this the same color blue as my Tahoe. I think it was Indigo Metallic irrc...

 

[Tonyrodz]

Private sale. Im not going back 3.5hrs. Just a hard learned lesson and moving forward. Like the truck, see the potential, just want to fix it even if its in stages. Progress is progress the way I see it

That's a great attitude to have. Karma is a real beyotch.

Heres a pic of the Yukon along with one of my Tahoe from a year ago. Not to get side tracked or off topic. End goal after everything is fixed is to respray this the same color blue as my Tahoe. I think it was Indigo Metallic irrc...

View attachment 262920 View attachment 262921

Awesome color

 

[TooTurntDad]

So as Im going through and swapping out my TCCM I noticed this wire hanging down and its to the harness. Not sure where it goes. Any ideas? Ill have to see if I can get a pin to put it back in the right spot.

 

[Fless]

So as Im going through and swapping out my TCCM I noticed this wire hanging down and its to the harness. Not sure where it goes. Any ideas? Ill have to see if I can get a pin to put it back in the right spot.

View attachment 263094

Here's a pic from my '04. Not sure what it powers, though.

 

[TooTurntDad]

Here's a pic from my '04. Not sure what it powers, though.

View attachment 263099

Got it, I have to get a pin or something to throw on it and put in the right spot.

Now, ended up finding out I got the wrong TCCM and turns out its not the same as mine even though it was said to be from an 03-06 yukon. So, that part is on standby for now. Moving on to the new actuator to replace for now.

Fixed my 2a fuse for my steering wheel controls but had no luck getting power for some unknown reason. No lights shine, no response when the buttons are pressed is there another fuse for this somewhere?

 

[Fless]

If the TCCM was from a Denali that would be a different system (all wheel drive); believe that's for the Borg Warner TC. Pretty sure that the TCCM has to be programmed to the vehicle unless it's a Dorman.

No clue on the steering wheel controls. If there's an aftermarket radio it would need a separate box for the steering wheel controls to actually operate the volume, etc.

 

[TooTurntDad]

If the TCCM was from a Denali that would be a different system (all wheel drive); believe that's for the Borg Warner TC. The TCCM has to be programmed to the vehicle unless it's a Dorman.

No clue on the steering wheel controls. If there's an aftermarket radio it would need a separate box for the steering wheel controls to actually operate the volume, etc.

The TCCM was bought off of ebay. It didnt come from the denali where I pulled the harness from. But I do have the body control module from that truck though. Not sure if I’ll need it unless I end up going from bench to rear heated captains chairs, which that truck still has.

Any ideas on what style pin I need for that one wire? I suck at naming things like this and getting the right thing once lol.

Also I am aware of the interface I need for the steering wheel controls. I actually prefer them over reaching to the radio. Love some comfort features like that.