T43: 2007 Escalade (2) Roms: 22" Rom and 18" Rom Calibration Speedo Adjustment

[raceghost]

Hi all,

New to the GM tuning, and have posted in the E38 Section a couple of times.

Purchased Truck used, blown motor, transmission, and rebuilt it all. Interesting had some issue with TCM and transmission acting up. Was suggested I check programming. TCM was flashed by GM Dealer upon NEW Transmission being put in. I went to a friend who has access to all the GM ROMS via official GM programming access. We found some things interesting. My Cadillac is the Luxury Version and came with the 22" Rim upgrade. When we hooked up to the programmer, we found (2) different calibrations for rims sizes. Both Calibrations are numbered and registered differently. Both of them have notes for 18" version, and 22" version respectively. I have attached them below. So the calibration on my truck was the 18" version, and reading all the nasty details, and GM warning labels on their ROM Flash site, it states, do not program TCM with wrong RIM size Calibration. We promptly updated it to the 22" TCM Version. I have used the EFI LIve to read both ROM's and versions, and done a comparison within the software to see the differences, they are subtle, and only in a couple of tables. But I digress, download them both, and do the compare for yourself. We also did a Shift Relearn or reset the adaptive data.

Note: If you have 18" rims and wish to go to 22"rims, then here is the latest updated ROMS for you. or visa versa, getting rid of 22" and going to 18". I did notice some subtle differences in transmission once I loaded the 22" version to my TCM.

My nest question, is Tire Size calculation.
I have attached a stock E38 Rom from my truck, as well as an updated rom for tire size and a couple of other things. Specifically, you need to check the Speedo Tables and relating tire size calculator tables. I think you will be horrified at what you find in the stock rom calibration on how the Speedo is calculated. You will see that the numbers in the stock rom are craxy, in fact, when you hit the tire calculator function, it tells you that the tire size is set fo 72" tires...lol. Check it out.

Either way, In the edited rom, you will see that I have it set for 285/45/22, specifically, the tires I have from Cooper say they are a 32" tire, not the calculated 32.10 that most tire calculators give you, this is directly from coopers website.
My issue is this. On the stock rom calculation, my spedo is about 4 MPH slow compared to GPS speeds. i.e., it says I am going 84 mph when I speedo and digital speed on the dash say 80. In the modified rom, with the 32" conversion, it is 3 mph off same way, GPS says 83, Speedo says 80~81.

Heres where it gets wacky, and I have tried multiple ways to close the gap to Speedo displayed=GPS to no avail. I have tried the 32 tires size with multiple adjustments to the "Speedo Fine Tune" table with in the EFI Live Speedo Calculator, where you plug in the Displayed speed and Actual Speed, no change. I have increased it 3 times by 2 miles per hour, each time it changes the "Pulses per mile" down by calculation, flash it back to the truck, with no change it is constantly 2 miles per hour off. I have even started over, set tire size to 32, 32.25, 32.5, 32.75, and 33, with no change either. Virtually I have played with all the tables within the first tab of the speedo parameters to no avail. I can't seem to close the gap below 2 mph variation, which makes no sense. i.e. stock rom to Speedo calculation adjustment for 32" tires closes the difference of 4mph down to 2 miles per hour, so one would think that increasing the tire size even more, would do the same thing...

So, then I got curious about what was in the same tables within the TCM. ON my older 05 Duramax, everyone stated never to do anything to the transmission with the TCM. I have read on the T43 to not do the same. But interesting is in the TCM programming, the speedo parameters are scaled for 30" tires. I am half convinced to run a test, and make the 32" adjustment to the TCM tables to reflect the same information that is in the E38 ECM tables. Mirror them if you will. Not touch any other tabs within the speedo parameters speedo calculator on both the TCM and ECM.

To clarify, what I am saying, is look at both my stock ECM and TCM files, and look within the speedo parameters, and click the speedo calculator, look at the first tab in both windows, and see the difference in how the ECM data looks to the TCM data within those tabs. Its like GM just completely hosed the handshake between the ECM calculations and TCM calculations...

Any help or thoughts would be greatly appreciated.

Thanks in advance

[izaks]

With the E38 / T43 combo, you have to make changes to both ECM and TCM (both the same steeings) to get the speedo to match the GPS

[raceghost]

With the E38 / T43 combo, you have to make changes to both ECM and TCM (both the same steeings) to get the speedo to match the GPS

Thanks bud. Much appreciated. I was thinking that once I stumbled across what I did.

Side not, hope I contributed for people who may have issues with a TCM programmed for 18" rims and change to 22" rims. I was shocked that GM made two separate calibrations for the same TCM/Trans and ECM no mechanical differences, just rim sizes.

[raceghost]

Tried your suggestion bud, and no dice. I mirrored the TCM to the PCM/ECM in respect to tire size and pulses, etc. still 2 mph off. Played with the fine tune speedo table as well, no dice. Not sure what to make of it. Verified that tunes are actually being written to the controllers as well.

[izaks]

Try increasing H0139 / H0136 by 1% at a time and see what difference it makes
If it goes the wrong way decrease them

[izaks]

Apologies
Reduce H0136 and increase H0139 by 1% at a time and see what difference it makes
Otherwise increase H0136 and decrease H0139

[raceghost]

Apologies
Reduce H0136 and increase H0139 by 1% at a time and see what difference it makes
Otherwise increase H0136 and decrease H0139

Yah, watching how changes are done when using the calculator, logic says to decrease H0136... and increasing H0139... Ill give that a run. and get back to you.

[raceghost]

SO played around some more, and playing with H0136 is the same as changing the Tire Diameter in the Calculator, and once you set it above 32, it does not close the gap on speed. I set it to 33 inches, which changes the H0136 table to 611 instead of 32" which is 630, and speedo is still 2 MPH off. Its like once you go above 32, it stops having any changes on the speedometer. Makes no sense.

I also measured my tires diameter which I know is rough math, and they sit with weight on them at approx 31.5" tall. Cooper's website says they are exactly 32" at 35psi on their website. My pressure is set to 35 respectively as well.

[minytrker]

Cheat the gear ratio if tire size is working.

[raceghost]

Cheat the gear ratio if tire size is working.

Forgive me, may sound naive, but I am not sure how to do that? Can you enlighten or educate me? Thanks

[izaks]

Try the following settings and let me know GPS and speedo readings
H0105 = 391.3
H0136 = 391.3
H0139 = 2556.1

[izaks]

Forget about using the speedo calculator - it never works
Where did the value in H0135 come from ?

[raceghost]

Forget about using the speedo calculator - it never works
Where did the value in H0135 come from ?

That was in the ROM when it was read as stock settings. I tired changing it to reflect the same pulses as in table H0101... Didnt seem to work. Secondly, I noticed another issue. In the The speedo calculator, on the VSS Pickup Teeth, it has 36... If you hit the drop down, 36 is not an option, it only gives you 17 or 40... Im wondering if the stock rom disassembly done by EFILive is incorrect. Like look at the stock rom I uploaded, and go into speedo and look at the crazy calculation that is in the stock rom with no modification to it. It states the tire size as 72" or 6 FT... I read that from the vehicle when I got it, so I had the theoretical stock rom that was on the truck before anything was touched. It makes no sense. I have been scouring the internet to see what the stock teeth count on the VSS Reluctor Ring is from GM to no avail.


Try the following settings and let me know GPS and speedo readings
H0105 = 391.3
H0136 = 391.3
H0139 = 2556.1

Are these in Metric? I am in the states and have things set to imperial... A little slow on the conversion..lol

[izaks]

Yes metric

[izaks]

632
100.26
For 31.9 diameter

[izaks]

100.57


630.0 for 32" diameter

[izaks]

I have no experience with 4wd, but it seems strange that H0152 and H0153 differ so widely

[raceghost]

632
100.26
For 31.9 diameter

Thanks, ya, lol, I was working it out...

As to the 100.26 in table H0139, I tried varying that from 99 to 102 with no change on its own. As to tables H0105 and H0136 I was very curious about those numbers as well, but since the calculator did not change the H105, I figured it was good data. Doesn't going from 630 to 632 in the H0136 table make the tire smaller? In essence I think we need to make the tire larger, and I did try 626 in that table when I plugged in 32.10 as the calculated diameter from 285/45/22 tire size, it did not however change anything.

[raceghost]

I have no experience with 4wd, but it seems strange that H0152 and H0153 differ so widely

I noticed this as well, and had not made my way to a question or hypothisis on that one either. Again, most tables where set based off of stock rom input, so if the calculator did not change it, I was reluctant to play with it...

[raceghost]

I have no experience with 4wd, but it seems strange that H0152 and H0153 differ so widely

Also, its is a AWD setup, yes has a transfer case, but the transfer case is only 4 high, no adjustments like a normal T case.

[izaks]

Changing H0136 in the ECM and TCM worked for me. I now have less than 1km/h difference from 80 120 km/hr speedo vs GPS

[raceghost]

Changing H0136 in the ECM and TCM worked for me. I now have less than 1km/h difference from 80 120 km/hr speedo vs GPS

Ok, Ill play a little more, its 4 A.M. where I am at, so I will give it a go in the daytime tomorrow. Also, any thoughts on the VSS Reluctor Ring setting? What is yours, also 36? Or is yours set to 40? I noticed on all GM sites it shows the 4l60E as a 40 Tooth. Seems rather odd that GM would make a 36 tooth, as well as EFI Live only having drop down menus for 17 or 40... This is in the Calculator vs the H0102 table. Table shows 36, but when you go into the calculator and select the Drop Down, mine only gives option of 17 or 40. Curious where the 36 came from. But it is set that way in the stock rom...hmmmmm.

Thanks again, and I will post back.

[izaks]

H0102 in mine is also 36
Sleep tight !

[raceghost]

Also, one last Question... Not sure if you saw my other thread: >( https://forum.efilive.com/showthread.php?29713-T43-2007-ERA-OS-24239353-CALID-24242131-or-24246751-Good-Performance-amp-Tow-Tune ) but curious if you have any of these settings as well for drivability you could share. Of course share it in that thread if you do. Ive been reading up on drivability issues I am having, and it seems these transmission need several drivability adjustments. I do not have a Tuner local or near by that is willing to do this. So any help over on that thread and matter would be awesome.

Thanks again, and get back you later today or tomorrow for you...

[raceghost]

Hey, Check this out: ( https://www.areds.com/wp-content/uploads/GM-Transfer-Case-CD-Web1.pdf ) This is a GM Schematic for the transmission and transfer case. By what it says, the Reluctor Ring size on the output shaft of the transfer case for speed sensor is 40T... I will try to verify this via other means tomorrow, but just thought I would throw it your way to see if you concur.

Thanks again,

[raceghost]

Ok, got what I needed to know. I visited 2 Transmission shops, as well as GM dealer, trying to Identify the actual Tooth Count in the 6L80 Transmission. One of the shops actually had a 2009 6L80 out of a Cadillac Escalade EXT.. Which the only difference is that I drive a 2007. Gm Verified no change between years of 2007 and 2009 respectively. as well as Transfer cases all have the 40 tooth in them as well. I counted the Teeth myself on both the 6L80 Trans, and the T-Case. and 2WD VS 4WD/AWD does come in to play here, which I will explain.

The input shaft 6L80 Reluctor ring is 36 Teeth
The Output Shaft 6L80 Reluctor Ring is 44 Teeth

The Transfer case Reluctor Ring is 40 Teeth

So, on a 2WD application only, the transmission does the speed sensing, and it is an Average of both input and output, so input being 36 teeth, and output being 44 teeth, the average of the 2 is 40 teeth.

On 4WD/AWD applications with use of Transfer case, the speed sensor is on the T-Case, where the output reluctor ring is 40 Teeth. This is the primary speed sensing, if it fails, the TCM will utilize the average discussed in 2 wheel drive applications.

GM Verified this in their parts department with parts schematics. One note to make, is I only have access to the USDM Markets. Not sure if other markets have different specs, but I would generally think not.

EFI Live has the H0102 tables incorrect, with 36 teeth, in both cases for my specific Transmission/Transfer Case TCM and PCM Combo.. This table should have 40 instead of 36.

To clarify, as to why the data is wrong in that table could be two things, either GM dorked the programming, or EFILive's disassembly calculations could have been fat fingered. I am not pointing this out for blame. I am pointing it out because we now have physical proof of teeth count as well as how the TCM calculates speed based off of 2WD or 4WD/AWD applications as it relates to my vehicle.

I am writing a Tune to reflect this specific issue and information to log and test. Will report back soon.

If this is the Case, we will need to do a Sticky to reflect this data, for everyone to look at and change older rom/calibration's as well as future calibration definitions.

Thanks, be back soon.

[raceghost]

This may be common knowledge, or might be some worthy information, but here we go.
Ok.. Things didn't go as planned, both positive and negative, and stumbled across some more questions, about failure and positive results. Here we go, I am going to step though it procedural as it happened, bare with me.

Step 1: Tables originally tried that got me within 2 mph:
23468
23469

Note: Not sure if it matters, but It might, I was flashing the TCM alone, or Flashing TCM first then ECM. Each time with fine tuning adjustments I was not seeing any change within 2 mph of GPS/Speedo. Almost as if the flash was not comp-leting, though everything stated and all procedures that are instructed in doing so were met, and completed. Either way, just a notation on the flashing procedure.

Step 2: Tables tried after finding out today, that GM 6L80E Input shaft teeth is 36, output shaft are 44, and T-Case output shaft is 40...
23470
23471

Flashed the TCM first, and then flashed the ECM second.
Loaded up 7.5 Scan option, and loaded up the DTV options, connected to TCM
I did a Fast Reset
I did a Fast Relearn (I wasn't exactly sure what I was doing within the procedure, and shifted into drive, then neutral then reverse, and the it just sat there and idle high, then dropped to idle, and then I shit off the truck...lol. Started truck and had no gear options... stuck in neutral)
I looked up procedure documented in another post and realized my error...lol
I did a Self Clean
I did a Fast Reset
I did an Adaptive Reset
I did an Adaptive Preset
I did Fast Learn
Shifted into Drive, put foot on the break, Idled up to 1500 RPM's, and ran through its paces, dropped back to idle, and then shut off for reset.
Started truck, verified I had gears, and started to drive.
Drove half a block and shift to second at part easy throttle didn't shift till 3500 RPM's and then shifted hard.
Revs in second stayed just as high, then it shifted hard to 3rd, again at part easy throttle.
I let off to see if it would shift out of torque, and it hard down shifted and then limped the trans, CEL/MIL light on, with codes P0700, P0756, P0776, and P2714 (all bad)

I pulled over safely, and investigated. I figured i Had done the Relearn process incorrectly, and checked it again.
I did a Fast Reset
I did an Adaptive Reset
I did an Adaptive Preset
I did Fast Learn
This time the fast learn idled up to 1300 RPMS, and then went though its shifts, though it seemed to take much longer this time...
I shut vehicle down once it came back to idle, and this time sat for 5 minutes to make sure that the TCM was not in learn mode anymore.
I started to drive, shift to second seem to happen around 3K rpm this time, and was a little easier, but still really firm, and then right before it shifted to 3rd, it abruptly shifted down to first and limped the trans, with the same DTC's...

In the Relearn thread here on EFI LIVE, I read a little more, and other people had stated that the relearn procedure for some reason had caused others unknown issues, and they had to reflash the TCM for it to return to normal procedure...
So I flashed the same settings from step 2 again with the VSS set to 40 rather than 36, and tried again.
Got a block and it limped the transmission again...

In my mind, being that I counted the teeth in a 6L80E on a bench, and all the information I received today, thought nothing of the 40 settings... And also thought, that the transmission finally just shit the bed,which with its eradic shifting issues even after replacing was my general assumption, and this just finally did it.

So I sat there, thought a little more, and was not ready to give up, so in an effort to limp it home before taking it down for a blown transmission, I decided to reflash the step 1 roms back into the ECM and TCM.
This time, procedure was Flash ECM first, Then TCM.
Finished all the steps there, and went for a drive. Shifted beautifully, and like it should, all seemed good. But now I had questions on verifying the 40 teeth being wrong, or right, so I pulled over and flashed the Step 2 40 settings back in. Drove a block, and limped the Trans. Same DTC's.

This posed so many questions about calculations of GM and or EFI Live in it's disassembly and where they came up with 36. If 40 is correct, the experience I am having is that there is another table that once you change VSS to 40, another table I can not see must need changed to to make the shifting calculations correct. I am basing it all off of what I counted on the bench today in reference to the teeth count of 36/44/40 respectively. This is one for EFI Live maybe to look at, and see if they see something when one of the engineers plugs 40 into that table and sees another table that must be changed, but I digress to someone with more knowledge than me.

Step 3: Tables that interestingly reflected corrected speedo closer to accurate gps reading:
23472
23473
Note: I made a couple changes that I and Izaks had been discussion throughout this thread, so please compare these 2 pics here in step 3, to the pics in step 1, i.e specifically with H0105, H0135, H0106, and H0153. If I had to bet, I would say it is table H0105 and H0136 being set the same that actually does the trick. Not discounting that H0101 and H0135 might also have something to do with it, however, when I played with the H0101 table, and just put different pulses into it, I got no change in speedo correction. So I assume it must not have great bearing, and that H0105 and H0136 are actually what needs to be correct.
I did a Self Clean
I did a Fast Reset
I did an Adaptive Reset
I did an Adaptive Preset
I did Fast Learn, let it do its thing. Shut off truck, sat for 5 minutes, and drove away.

I tested with Step 3 Settings, and my speedo was now a mile off, but exactly a mile off thoughout the entire speedo function. Before, utilizing step 1's settings, speed below 45 on speedo was higher than GPS, and then it would flip at higher speeds tested to 80 on speedo and gps would say 82... So a ratio or percentage was off somewhere...

Step 4: Here are my final tables, that yeild perfect speedo to gps operation exactly on at every speed between 1 and 80 mph... I tested at 5 mph intervals for 1 miles, for every interval, took about 20 minutes.
23474
23475

In Conclusion:

I believe it is table H0105 and H0136 that have the greatest effect on speedo calibration within the ECM, and H0136 as well in the TCM.

I still can't wrap my head around the teeth count counted on a 09 6L80E Input Shaft at 36, Output shaft at 44, and the T-Case output shaft at 40, and the GM dealer ship as well as transmission shop stating the 2WD platform uses an average between the input shaft and output shaft = 40, and that in 4WD/AWD platforms they use the T-Case 40 tooth to do speed. Like I said, I counted them myself on the bench today, and we looked in GM schematics for my VIN at the GM dealer... So if this is correct, I still think that there is a calculation that is within the ROM definition that is incorrect.

Hope this helps others.

Thanks for following and reading. Would love feedback from some of the guru's.

[joecar]

There's a lot of info there, I have to read thru it slowly, I'll get back in a few days.