Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum banner

2002 Trailblazer Encoder Motor/TCCM problem

9K views 4 replies 3 participants last post by  will168 
#1 ·
Hi Everyone,

Here is my story- I have Trailblazer 2002. Initially I swithed the nob from 2WD to Full 4WD, the light kept blinking but didn't feel any engaging, and once in a while this also triggered Service 4WD light on. Brought the car to dealer and it was told Encoder Motor problem and costed $630 to replace(if only I found this forum earlier at that time, based on the high TCCM failure rate on 2002 model, I would replace Transfer Control Case Module first).

When I picked the car(after the shop closed), I got Service 4WD light on right away and the switcher no longer got any light. Brought back to dealer again and this time it was diagnosed as "Found encoder motor over extending due to clutch lever and bearing in transfer case worn. Transfer case needs to be removed to replace lever and bearing" and would cost $1500 later reduced to $1000. I took the car back and bought an used 2005 TCCM for $85. Easily replaced TCCM based on the reading from this forum, disconnect/reconnected battery. Service 4WD light is still on every time I start car.

I feel the dealer misdiagnosed the problem at first time, it could well be the TCCM issue. But when they replaced the Encoder Motor, somehow they caused more issues because it did take them two days to replace the motor and was told they ordered the wrong part the first time. I don't fully understand what the second diagnose statement mean, but again this may not be fully true.

Here are my questions:

1) Does anyone understand what they talk about ? Could this be caused by wrong installation or put the wrong part on ? I am so surprised they didn't find this before when they were replacing the part and just gave the car back to me.

2) Where is the Encoder Motor located ? It will be great if anyong posts pictures. I want to take a look the area because I am not fully trusted what the dealer saying.

3) Any other things I can try to figure this out.

Thanks a lot for your help !
 
See less See more
#2 ·
The encoder motor is bolted to the side of the transfer case. Exploded parts diagrams are available on www.compnine.com for more detail.

It's impossible for anybody here to get in the middle of a dealer dispute, since you might have to escalate it to zone management. If you think they gave an incompetent or poor diagnosis, call GM to get a case number open, and follow the process.
 
#3 ·
Thanks Roadie. I have read lots of your posts in this forum. Have learned a lot from you.

Not try to get dispute with the dealership, but not happy with their services. Just want to see if this is something I can learn to fix myself.

The link diagram doesn't show encoder motor. Do I have to jack the front vehicle to see it ?

Thank you.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top