Calibration problems

[ScarabEpic22]

I was tuning a 2002 I6 last week and when I adjusted tables B1123, B1124, and B1125 in OS 12587430 it would force the 1-2 shift to occur right before 4000rpms at 30mph. It took me about 3 hours to figure out what was wrong as these tables work perfectly in my 2002 OS 12575262. With these values back to stock everything worked fine, but as soon as I set them to anything other than stock with OS 12587430 this weird shifting issue would occur.

Any ideas?

[ExtTB]

yea my computer acts strange since the new os..now my cruise doesnt work sometimes..shut off while i had it on today..I have up'd the pressure since my tranny slips alot between shifts at 210,000

[ScarabEpic22]

OK I can confirm this occurs in ALL P10s with this OS, I have another customer who is reporting the same problem with this same OS. Any updates as to what's causing this issue? Or am I just going to have to set them back to stock to bypass the calibration issue?

[ExtTB]

the tranny programming is strange...seems like raising the pressures is about all I can do... even when I change the shift speeds(partial throttle) it will double bump or act weird....I have 210,000 miles and understand stand why no tuning house messes with the tranny other than firmer shifting....it is easy to finish it off...mine slips?( rpms spin way up) between shifts unless I keep the line pressures up 20% ...

[ScarabEpic22]

Sounds like you're due for a rebuild man, if you're getting any flare (as in RPMs keep rising when a shift it happening but before it actually shifts) you need a rebuild. Upping the LPs is a bandaid, just postponing the inevitable.

I can adjust everything except these 3 tables in this one OS without issue, Ive only done 5 P10s but 2 are with this older 02 OS.

[ScarabEpic22]

Bump to the top as this is affecting a bunch of people now. Whenever an 02 P10 is flashed by the dealer it gets this OS so whenever you tune it it becomes and issue.

[Chevy366]

On the 06 TBs they did a TCC lockup update in the P12s for fuel economy .
I posted a link to GMs TIS update , check out and see what the TIS update does for the P10 .
http://tis2web.xw.gm.com/tis2web

[ScarabEpic22]

The biggest thing is the latest update adds more fan tables to the OS, as in they flat out do not exist in my early 02 OS.

Looks like some of the other segments that were updated enhance idle stability (pretty sure I took care of this with copying 05 tables over), 1-2 shift feel and stability (didnt see any difference between the later OSs and mine, must be behind the scenes), and of course more fan tables in later releases.

I might have to look through the later OS files I have here and compare them to my stock early OS. Really wish I could full flash this dang thing, wouldnt have to go pay a stealer $75 to do it.

[goldbergv95]

you know its funny when i put these values in stock it shifts fine but when i adjust it to something else it feels weriod. im guessing it does occur if you have the latest os reflash. thanks for letting us know expert erik!

[goldbergv95]

The biggest thing is the latest update adds more fan tables to the OS, as in they flat out do not exist in my early 02 OS.

Looks like some of the other segments that were updated enhance idle stability (pretty sure I took care of this with copying 05 tables over), 1-2 shift feel and stability (didnt see any difference between the later OSs and mine, must be behind the scenes), and of course more fan tables in later releases.

I might have to look through the later OS files I have here and compare them to my stock early OS. Really wish I could full flash this dang thing, wouldnt have to go pay a stealer $75 to do it.

Erik, I figured out the problem. The reason those three calibration that you changed didnt work has something to do with the shift 1>2 trans pressure. Today, i set the trans pressure back to the orginial OS calibration and the ride was just perfect. The one from the updated OS seems to slow the truck down from shift 1 to 2 area. :secret:

So try calibrating the trans pressure from the previous OS. It should help the B1123, B1124, and B1125 work at its advantage.

[ScarabEpic22]

Erik, I figured out the problem. The reason those three calibration that you changed didnt work has something to do with the shift 1>2 trans pressure. Today, i set the trans pressure back to the orginial OS calibration and the ride was just perfect. The one from the updated OS seems to slow the truck down from shift 1 to 2 area. :secret:

So try calibrating the trans pressure from the previous OS. It should help the B1123, B1124, and B1125 work at its advantage.

Its not trans pressures, what it does is switch the PCM to think its operating in 4WD, check out the 4WD shift settings they will be dead on.

[goldbergv95]

Its not trans pressures, what it does is switch the PCM to think its operating in 4WD, check out the 4WD shift settings they will be dead on.

4WD shift settings? Where is that on the efilive program? I removed my 4x4 drive shaft so i no longer have 4x4 features.

[ScarabEpic22]

4WD shift settings? Where is that on the efilive program? I removed my 4x4 drive shaft so i no longer have 4x4 features.

Irrelevant, having 4WD or not makes 0 difference here because the tables are there regardless of if you are 2WD or 4WD. What I found is when those calibrations are adjusted in this certain OS (in my 12575262 OS they work fine) the 1-2 shift happens at 4000rpms at 30mph. This only happens are WOT, if you go 80% throttle its fine IIRC. Basically the code address for these parameters is interfering with the code address of the 4WD WOT shift parameter and causing the PCM to automatically think its in 4WD and use the 4WD WOT shift pattern.

[goldbergv95]

Irrelevant, having 4WD or not makes 0 difference here because the tables are there regardless of if you are 2WD or 4WD. What I found is when those calibrations are adjusted in this certain OS (in my 12575262 OS they work fine) the 1-2 shift happens at 4000rpms at 30mph. This only happens are WOT, if you go 80% throttle its fine IIRC. Basically the code address for these parameters is interfering with the code address of the 4WD WOT shift parameter and causing the PCM to automatically think its in 4WD and use the 4WD WOT shift pattern.

Ive compare the stock settings from the update OS to the 32 max and the orginal OS and they all seem to be the same, seems suggish under the updated OS trans pressure. Except when i use the trans pressure settings from the orginial OS the 32 max speed seem to work just fine similar to when i use to have the orginial OS tune.

damm that sux! So your saying is rather than the 1-2 shift occurring from 30mph the 4wd WOT shift occurs causing the truck to feel suggish? Then what happen to your friends tune then since this problem occurs? Did you leave it back to stock settings for him?

[ScarabEpic22]

Ive compare the stock settings from the update OS to the 32 max and the orginal OS and they all seem to be the same, seems suggish under the updated OS trans pressure. Except when i use the trans pressure settings from the orginial OS the 32 max speed seem to work just fine similar to when i use to have the orginial OS tune.

damm that sux! So your saying is rather than the 1-2 shift occurring from 30mph the 4wd WOT shift occurs causing the truck to feel suggish? Then what happen to your friends tune then since this problem occurs? Did you leave it back to stock settings for him?

No, this should have NOTHING to do with trans pressures, IIRC I reset the line pressures back to stock in an attempt to track down the problem and if I touched those tables it still messed up the shift. What is happening is when the values of those 3 tables are altered and you go WOT in 1st gear, if short-shifts at 4000rpms (at 30mph for the customers 3.73 gears). If you look at table D1216 "WOT 1->2 Shift, 4WD Mode" the stock value is 4000rpms, the exact same value that the shift is occurring at when these tables are modified. It is NOT in 4WD at all, there is a bug that occurs when these tables are altered causing the PCM to incorrectly use the WOT 4WD 1-2 shift table instead of the normal WOT 1-2 shift. The fix, simply do not alter the tables in that one OS, I have tested it on 4 or 5 other P10 OSs and only the latest 02 one is affected.

[joecar]

Just a thought: if your calibration has D0960,1,2 "Throttle Kickdown" (or similar tables) make sure these are all set to 100%.

[goldbergv95]

No, this should have NOTHING to do with trans pressures, IIRC I reset the line pressures back to stock in an attempt to track down the problem and if I touched those tables it still messed up the shift. What is happening is when the values of those 3 tables are altered and you go WOT in 1st gear, if short-shifts at 4000rpms (at 30mph for the customers 3.73 gears). If you look at table D1216 "WOT 1->2 Shift, 4WD Mode" the stock value is 4000rpms, the exact same value that the shift is occurring at when these tables are modified. It is NOT in 4WD at all, there is a bug that occurs when these tables are altered causing the PCM to incorrectly use the WOT 4WD 1-2 shift table instead of the normal WOT 1-2 shift. The fix, simply do not alter the tables in that one OS, I have tested it on 4 or 5 other P10 OSs and only the latest 02 one is affected.

damm bug! I will try to give the dealer a call to see if they can reflash to the previous OS if it works.


Just a thought: if your calibration has D0960,1,2 "Throttle Kickdown" (or similar tables) make sure these are all set to 100%.

Yes we have d0960,1,2. But ill give it a try to see how it works. Ill let you all know tonight.

[goldbergv95]

well i tested it and based from the do960 to d0962, d0960 was already all 100 so nothing changed for the 1-2 shift except the 2-3 and 3-4 shift was better.

Erik is right. there is a bug on the 02 OS prob go to the dealer and try to reflash to the previous OS thats if they would allow it...

[ScarabEpic22]

Just a thought: if your calibration has D0960,1,2 "Throttle Kickdown" (or similar tables) make sure these are all set to 100%.

I always have those set to 100%, I tried playing around with lower values a few years back to get it to drop into 1st under moderate WOT but found it was just better to leave them alone.


well i tested it and based from the do960 to d0962, d0960 was already all 100 so nothing changed for the 1-2 shift except the 2-3 and 3-4 shift was better.

Erik is right. there is a bug on the 02 OS prob go to the dealer and try to reflash to the previous OS thats if they would allow it...

Shouldnt effect the 2-3 or 3-4 shifts at all??

Yep, the 02 P10 OS 12587430 has this issue. Thats the only one Ive found so far, the rest seem to be ok (but Ive only messed with a select few OSs).

[goldbergv95]

no i ment the 2-3 and the 3-4 felt a little bit faster which is much better since im into performance. just trying to find a way to reflash to the previous os