Update to adding trans temp gauge...

[BigBadSubaru]

Nope, I don't have the steering wheel controls :-( It's got the Bose sound system but that's about the only "fancy" option... Looked at pick n pull today for a steering wheel with buttons but no luck :-(

 

[Leon200]

Hello, Thanks for sharing your work DougAMiller. Nice stuff. About a year ago I used your thread to help me recode and install a used Cluster out of a 04 Tahoe into a 04 Yukon Denali.

I had the same brake booster service problem when I changed out the clusters. My Denali has a hydraboost brake system and the donor Tahoe was vacuum.

To make a long story short, I felt that the first two lines of the code were corrupted from my original Denali Cluster read so I wrote the top two lines of code in from the tahoe. This gave me the booster nag.

I took things apart again today and wrote the original top two Denali lines back into the code and refalshed the Atmel 25020 chip. Now the Booster nag is gone and all is working like it should. This is what leads me to believe that the booster code must be in the top two lines somewhere.

I will try and upload them so someone can look at them.

 

[DougAMiller]

Hello, Thanks for sharing your work DougAMiller. Nice stuff. About a year ago I used your thread to help me recode and install a used Cluster out of a 04 Tahoe into a 04 Yukon Denali.

I had the same brake booster service problem when I changed out the clusters. My Denali has a hydraboost brake system and the donor Tahoe was vacuum.

To make a long story short, I felt that the first two lines of the code were corrupted from my original Denali Cluster read so I wrote the top two lines of code in from the tahoe. This gave me the booster nag.

I took things apart again today and wrote the original top two Denali lines back into the code and refalshed the Atmel 25020 chip. Now the Booster nag is gone and all is working like it should. This is what leads me to believe that the booster code must be in the top two lines somewhere.

I will try and upload them so someone can look at them.

That doesn't seem to fit with my research. The first two lines appear to me to be all odometer. Maybe you're formatting is such that the first two lines are longer and include data from past the odometer.

 

[NoReverseYukon]

@DougAMiller

Have you made anymore progress on deciphering these BIN files ?
What are your thoughts on the axle ratio being somewhere in there ?

I have 2 clusters with the trans. temp gauge that have inaccurate speedometers. 1 is approx. 10% fast and the other is slow. This is leading me to believe that the axle ratios from the vehicles that these came from are different than what is in my Yukon. I am waiting on an eeprom reader from Amazon and have HxD and Notepad++ to work with, but this will all be a relatively new venture for me, so any pointers will be appreciated.

 

[DougAMiller]

@DougAMiller

Have you made anymore progress on deciphering these BIN files ?
What are your thoughts on the axle ratio being somewhere in there ?

I have 2 clusters with the trans. temp gauge that have inaccurate speedometers. 1 is approx. 10% fast and the other is slow. This is leading me to believe that the axle ratios from the vehicles that these came from are different than what is in my Yukon. I am waiting on an eeprom reader from Amazon and have HxD and Notepad++ to work with, but this will all be a relatively new venture for me, so any pointers will be appreciated.

I haven't. I've gotten side-tracked with other things and haven't gotten any further.

As for the axle ratios, they certainly could be stored in there, but I have never run across anyone saying that the cluster had to be calibrated to their axle. The places that do programming only ask for mileage and hours, I've never seen anyone indicate that they need the axle ratio, so I'm skeptical that it is stored there. It seems more likely that it's in the PCM. That said, I can't explain your experience.

 

[Tonyrodz]

I haven't. I've gotten side-tracked with other things and haven't gotten any further.

As for the axle ratios, they certainly could be stored in there, but I have never run across anyone saying that the cluster had to be calibrated to their axle. The places that do programming only ask for mileage and hours, I've never seen anyone indicate that they need the axle ratio, so I'm skeptical that it is stored there. It seems more likely that it's in the PCM. That said, I can't explain your experience.

Messing with my tech 2 there was an option to change tire size--so different, but similar. Tire size will def affect your speedo.

 

[NoReverseYukon]

Messing with my tech 2 there was an option to change tire size--so different, but similar. Tire size will def affect your speedo.

I thought so too, but changed mine from 265/70/16 ( stock ) to 285/75/16 and it didn't do squat. Since I had to press on the brake pedal to complete the change, I think this only affects the ABS.

 

[DougAMiller]

I thought so too, but changed mine from 265/70/16 ( stock ) to 285/75/16 and it didn't do squat. Since I had to press on the brake pedal to complete the change, I think this only affects the ABS.

I've seen that in my Tech2 as well, but I've never played with it. I have always assumed that it was to calibrate the speedometer to the tire size. I'm not sure what other reason there would be for it.

As to reprogramming the cluster, your sig shows an '01 Yukon. Those have an older cluster design than the 2003-2006. I'm not sure what will be different in the earlier ones, since I have never played with one. I do know that the stepper motors and displays are different, so information stored in any EEPROMs on those clusters may be significantly different.

 

[NoReverseYukon]

I've seen that in my Tech2 as well, but I've never played with it. I have always assumed that it was to calibrate the speedometer to the tire size. I'm not sure what other reason there would be for it.

As to reprogramming the cluster, your sig shows an '01 Yukon. Those have an older cluster design than the 2003-2006. I'm not sure what will be different in the earlier ones, since I have never played with one. I do know that the stepper motors and displays are different, so information stored in any EEPROMs on those clusters may be significantly different.

Question for you, Doug.

Should a sweep test cause the needle to go all the way to 120, or should it stop half-way? I asked this on another thread
https://www.tahoeyukonforum.com/thr...t-inaccurate-speedometer.124695/#post-1539227
but received no answer.

Thanks.

 

[DougAMiller]

Question for you, Doug.

Should a sweep test cause the needle to go all the way to 120, or should it stop half-way? I asked this on another thread
https://www.tahoeyukonforum.com/thr...t-inaccurate-speedometer.124695/#post-1539227
but received no answer.

Thanks.

When I do a sweep on mine, it goes full-scale, but as I was saying before, 2001 may be different compared to 2005.

 

[exp500]

Many Thanks Doug! I've been lurking since finding your posts, and learning alot! Keep up the good work!

 

[Leon200]

That doesn't seem to fit with my research. The first two lines appear to me to be all odometer. Maybe you're formatting is such that the first two lines are longer and include data from past the odometer.

yes, you are correct. I was mistaken. The code is likely not in the top two lines of code. The service brake booster nag came back after a few days. I wish it would go away again!

 

[DougAMiller]

yes, you are correct. I was mistaken. The code is likely not in the top two lines of code. The service brake booster nag came back after a few days. I wish it would go away again!

I don't know where the brake booster config is stored, but it doesn't seem to me that they would put it in the cluster. To me it would make more sense for that to be stored in the either the ABS, BCM or PCM module. I would guess that it will require reprogramming one of those.

 

[hatzie]

I thought so too, but changed mine from 265/70/16 ( stock ) to 285/75/16 and it didn't do squat. Since I had to press on the brake pedal to complete the change, I think this only affects the ABS.

Your tire size & axle ratio make a final drive ratio for two computers in your truck. ABS and PCM.
The ABS cal is important but not the only piece of the puzzle. A Tech2 can change the ABS tire size calibration but not the final drive ratio in the PCM. I'm not sure you can use the Tech 2 to re-calibrate the ABS controller for a different axle ratio. Likely you can do at least the ABS tire size calibration with some of the high end Autel and SnapOn diag tools but do your own research.
The PCM handles calibration of vehicle speed data to the instrument panel over the GM Class II Serial databuss. You'll need to use a tuner package to directly program the PCM or a modified Cal file from GM to program the PCM over AC Delco TIS web. Good luck getting a modified Cal file from GM even if you're a dealership. I used HP Tuners to change from 245/75R16 to 265/70R17 tires on my 2005 K2500HD. Supposedly some of the handheld tuners can modify this PCM parameter.

 

[hatzie]

Question for you, Doug.

Should a sweep test cause the needle to go all the way to 120, or should it stop half-way? I asked this on another thread
https://www.tahoeyukonforum.com/thr...t-inaccurate-speedometer.124695/#post-1539227
but received no answer.

Thanks.

Jeffescortlx has several 2nd gen GMT800 cluster repair videos up. More than one shows a proper needle sweep using a Tech 2 on his bench.
https://www.youtube.com/channel/UCzJWy4r_V89YYt4GBxNaJfQ

 

[alaska_guy]

I don't know where the brake booster config is stored, but it doesn't seem to me that they would put it in the cluster. To me it would make more sense for that to be stored in the either the ABS, BCM or PCM module. I would guess that it will require reprogramming one of those.

You can remove the brake booster message by shorting the two outer pins on the connector. I did this on my suburban.

 

[alaska_guy]

Hp tuners will allow you to fix the axle ratio and brake booster message. If I had my suburban still I would of been able to tell you what two wires to tie together to get rid of that message. It's looking for a normally closed circuit.

 

[Logan5]

Want to say thanks to OP for great info and report successfully adding Trans Temp gauge to my 05 Tahoe.

Only difference was the trans temp hex was '03' and needed to be changed to '42' which I found in some YT vids.

I ended up using:

Amazon.com

and

Chironal 2set SOIC8 SOP8 Welding Wire +2pcs Board Test Clip+ Two Boards for EEPROM 93CXX/25CXX/24CXX in Circuit Programming on USB Programmer TL866CS TL866A EZP2010 (2Pcs Board): Amazon.com: Industrial & Scientific

Chironal 2set SOIC8 SOP8 Welding Wire +2pcs Board Test Clip+ Two Boards for EEPROM 93CXX/25CXX/24CXX in Circuit Programming on USB Programmer TL866CS TL866A EZP2010 (2Pcs Board): Amazon.com: Industrial & Scientific

www.amazon.com

 

[Ilikemtb999]

Want to say thanks to OP for great info and report successfully adding Trans Temp gauge to my 05 Tahoe.

Only difference was the trans temp hex was '03' and needed to be changed to '42' which I found in some YT vids.

I ended up using:

Amazon.com

and

Chironal 2set SOIC8 SOP8 Welding Wire +2pcs Board Test Clip+ Two Boards for EEPROM 93CXX/25CXX/24CXX in Circuit Programming on USB Programmer TL866CS TL866A EZP2010 (2Pcs Board): Amazon.com: Industrial & Scientific

Chironal 2set SOIC8 SOP8 Welding Wire +2pcs Board Test Clip+ Two Boards for EEPROM 93CXX/25CXX/24CXX in Circuit Programming on USB Programmer TL866CS TL866A EZP2010 (2Pcs Board): Amazon.com: Industrial & Scientific

www.amazon.com

Did you use the provided software?

 

[Logan5]

Did you use the provided software?

No I have a Mac, and the provided software was Windows only. I ended up using:

David Griffith / minipro · GitLab

An open source program for controlling the MiniPRO TL866xx series of chip programmers

gitlab.com

Which looked hard but was surprisingly easy.