4X4 stopped working

[JamHodge]

NEED Advice ! I have a 2007 Tahoe LTZ that I bought new in 2006. I don't drive it much so it has 68,000 miles. The other day I went leave, it was snowing out and my four wheel drive was not working. When turn the selector to Auto the light stays in 2wheel drive. If I turn the selector to 4wheel HI most of the time the light blinks for 2 couple seconds the then 4Wheel drive light comes on. BUT it is not in 4X4. I checked the 2 fuses in the fuse panel ( #42 & #70 ) and both are ok.
With the car off in my quiet garage I turned the key on and turned the selector to 4x4 HI and I do hear a noise (like a electric motor) in the front end area. But still the 4x4 is not working. Does anyone have any experience with this problem ?

 

[Donut Slayer]

What kind of codes is it throwing? Could be a encoder motor or the actuator on the front diff.

 

[JamHodge]

Thanks for replying Donut. My check engine light came on about a year ago. But when I got it checked out it was one of four O2 sensors. I never pinpointed which one so the light is still on. I guess I'll go today and see if there are anymore new codes . How do I check the actuator ? And what is that encoder motor ?

 

[Donut Slayer]

I dont know offhand if the code would illuminate the CEL, but the encoder motor will set a code that will read "service 4wd" or something like that on the DIC(driver info center). The code is C0327. The encoder motor is the electronic motor that shifts the transfer case into 2wd,4hi, 4lo and such. They are a known issue with GM. The new ones fix the problem. You can get a updated one from online places like autorock.com if thats your problem. Other than that, I dont know how to trouble shoot the actuator. Its in the front diff and just screws out IIRC. Has a wire plug attached to it.

 

[IronMan4Real]

Encoder motor

 

[Shmell]

check your TCCM...had the same problem with mine after getting a U0102 code
swapped the module and the problem was solved

 

[smorrow]

What part number did you use?
I see a Dorman 599-144, but it does not show it is the TCCM for a 07 Tahoe.
i have the same problem and am not finding much help.

 

[JamHodge]

I am not sure what the part number is four Dorman. But it was the encoder motor it is not hard to install

 

[smorrow]

Thanks,

I have the U0102 code now with scc 4wd on dash.
I have seen things from a bad Transfer Case Control Module, an Encoder Motor, 4wd position sensor, transfer case shift control either the switch or module.

I have no idea where to begin and which one it is. Most of the parts are not cheap either to just throw them in and see if it works.

I noticed that the yellow light on the 4wd switch sometimes is on and other times it is out.

 

[smorrow]

Donutslayer
My code is u0102 with the same "service 4wd" on dash. This code says "lost communication with transfer case".

Do you think that is also the encoder motor or something else like the TCCM

I dont know offhand if the code would illuminate the CEL, but the encoder motor will set a code that will read "service 4wd" or something like that on the DIC(driver info center). The code is C0327. The encoder motor is the electronic motor that shifts the transfer case into 2wd,4hi, 4lo and such. They are a known issue with GM. The new ones fix the problem. You can get a updated one from online places like autorock.com if thats your problem. Other than that, I dont know how to trouble shoot the actuator. Its in the front diff and just screws out IIRC. Has a wire plug attached to it.

 

[smorrow]

What was the part number for the TCCM you used?

check your TCCM...had the same problem with mine after getting a U0102 code
swapped the module and the problem was solved

 

[JamHodge]

Sorry buddy I can't answer that i'm not a mechanic.