Service 4WD light

[strtrdrf4i1]

I just bought a used 05 Z71 Tahoe. I love the look and ride it is awesome. When driving from the place of purchase the service 4wd light came on . I had an 06 Chevy avalanche (same Platform) that had the same issue. i ended up getting rid of it because the dealership could not figure it out and i did not want to deal with the headache. Does any one have any suggestions or idea on what this could be.

To give a little info the truck has roughly 130K on the engine, one owner from Maryland clean and rust free. Even in the under body, which was a little shocking for Maryland. Does anyone have any suggestions on maintenance to get done now at this mileage to ensure the longevity of the truck, Thank you for your time.

 

[mdavenport]

For the Service 4WD I have read it could be the encoder motor for the transfer case or the switch. I would do an Internet search on it, possibly the Z71 Tahoe/Suburban forum, for more info. Seems like most threads on here go unanswered. Hope this helps.

 

[mdavenport]

Also I would definitely service your transmission if you are unsure when it was last performed. The 4L60E can be very finicky.

 

[magyukon]

Hi,

I'm not sure if it can help, but I had the same issue on my 2005, 2500 Yukon XL. Service 4WD light came on and off randomly.

I got it to the dealer and they just clean the encoder connector. Seems to work for some times...

Few months later, I ended up having to replace the transfer case. The shaft inside got loose a little bit over time and that's why the light was getting on and off.

So, I suggest to start looking at the transfer case first. If it's same problem as mine, maybe you can repair it before you have to replace it like i did.

Hope it can help !

 

[bluetahoe2211]

1st check the "trec" fuse under the hood 30amp. Then go to the switch on the dash. Some ppl say the solder on one of the main pin points cracks. Lastly electronically you have the harness at the transfer case. Im not really sure how to check if its functioning properly or not. Im assuming you could unplug it and test it with a meter. Be careful though because i believe there are 2 diff harnesses. If your good in thos three areas then two remain. The tccm (transfer case control module) and the transfer case ring which is located in the motor. Its unlikely that you will have to replace the entire motor which is expensive. The ring is like 60-80 bucks. I have some detailed info for that if you want it.

 

[bluetahoe2211]

The fuse could also be under atc but mine is an '03 and its trec. Bottom right if your standing on drivers side i believe.

 

[bluetahoe2211]

http://www.gm-trucks.com/forums/topic/82874-service-4wd-c0327/

 

[bluetahoe2211]

What i call the transfer case ring is also known as transfer case encoder motor sensor