E40/T42 no ISS Trans tune.

[jhbau1000]

Never mine they have the normal shift set to call for TCC for 3rd and 4th. All other patterns are set to not use tcc. So i will give them a try.

[jhbau1000]

Crap i think I have to pay another $200 to just change the T42. Anyone know how to change it with out hp tuners.

[gtstorey]

available on ebay programmed to vin for $80

[jhbau1000]

Ok here is a drive log from today. Cold to 170 was as hot as I could get it. I also changed all the settings to the GTO tune file.But I did not update the whole T42 to the GTO because I did not want to spend the money on changing it unless I have too. It seemed to hold but every time it down shifted it would go back to lockup hold for 10 sec then kick out and throw the P0741. I then had to clear code for it to kick back in.

[TransGo Robert]

Ok finally making some progress. In this last log your converter is not slipping at all. However something is not right in your tune because it thinks it is slipping. It looks like it is reading the unexisting turbine speed sensor. I am using a math channel to calculate the slip myself and as you can see in this screenshot where i put the light green boxes it is not slipping at all, however if you look where I put the red boxes the computer thinks it is slipping by the same amount as the engine RPM since it sees the transmission input shaft at 0 RPM all the time.

Slip.png

[jhbau1000]

So what can we do about that. I have the ISS turned off in tune.

[TransGo Robert]

So what can we do about that. I have the ISS turned off in tune.

Hopefully someone else on here can help with that. I know transmissions real well, but the tuning side I don't know well at all.

[Shrek]

Ok here is a drive log from today. Cold to 170 was as hot as I could get it. I also changed all the settings to the GTO tune file.But I did not update the whole T42 to the GTO because I did not want to spend the money on changing it unless I have too. It seemed to hold but every time it down shifted it would go back to lockup hold for 10 sec then kick out and throw the P0741. I then had to clear code for it to kick back in.

The T42 TCM operating system (OS) that you are using (24235341) is intended for use with an ISS (15-pin 4L65).

Coping over GTO settings does not address the issue of the numerous algorithms and diagnostics that run in the background - which are expecting an ISS signal.

In other words - trying to mimic a GTO calibration within your existing OS will not work.

Tuning software only affords access to a very small portion of the overall calibration.

[Shrek]

So what can we do about that. I have the ISS turned off in tune.

With many T42 operating systems, using tuning software like HPT to change the "ISS Fitted" parameter (TCM 492) from "Enabled" to "Disabled" - accomplishes the square root of bugger all.

[TransGo Robert]

accomplishes the square root of bugger all.

[jhbau1000]

Ok so if a different T42 operating system (OS) will fix my problem I'm all for it. But I'd like to be sure before I speed more money on another tune file. Plus I need to know which operating system (OS) i need. The tune repository has 2 for the 2006 GTO. OS 24231674 & 24236195.

[Shrek]

T42 TCM OS 24231674 was used in the 2005 GTO.

T42 TCM OS 24236195 was used in the 2006 GTO.

GM uses a numbering system (OS number) to catalogue calibrations.

As OS updates (or new calibrations) are released - the OS number increases (increments positively).

[Alvin]

I've said it before.. I've deliberately turned off ISS on a bunch of 4l70 and 80's and have never had a ill effect.

If you need to calculate slip use engine RPM

[Shrek]

As I have said before ... some 15-pin T42 operating systems seem to work OK (never perfect) when used to control a 13-pin 4L60 - other T42 operating systems will not consistently / correctly lock the torque converter.

Many people don't notice the torque converter not locking - especially the ones that only drive their pride and joy a few times per year.

I have done dozens of these systems - thanks to a local transmission shop that only builds 13-pin 4L60/65 transmission for LS conversions.

[jhbau1000]

I understand that some T42 OS's work better than others with the 13 pin transmissions. I know on the OS I'm running now setting the ISS to disable seems to do nothing. It show the TCC slip RPM's matches the engine RPM's and calculates the slip at 90% which causes DTC P0741 to come on. If i disable the DTC P0741 then it will throw DTC P0894. I'm trying to find out what T42 OS do I need.

[Alvin]

As I have said before ... some 15-pin T42 operating systems seem to work OK (never perfect) when used to control a 13-pin 4L60 - other T42 operating systems will not consistently / correctly lock the torque converter.

Many people don't notice the torque converter not locking - especially the ones that only drive their pride and joy a few times per year.

I have done dozens of these systems - thanks to a local transmission shop that only builds 13-pin 4L60/65 transmission for LS conversions.

Never had one not lock up TCC. Prehaps you can share a file/log showing this?

[jhbau1000]

The transmission is locking up now. Transmission shop fixed the issue of it not holding lock. Problem is computer still thanks its slipping so it throws a p0741. I do have access to my log data as I'm at work now. There is a log up a few replys that have a log.

[Alvin]

The tune file you posted has a bunch of odd TCM codes turned off. DO you have the stock unmolested file to compare to?

In the meantime maybe leave ISS fitted (first page of transmission section) to enabled but just turn of the diagnostics for it. This is how I do it. I'd also do a speedo calibration even if your inputting the exact same numbers. These year ranges are kinda notorious for having the TCM setup for a 3.42 and the ECM setup as a 3.73. I can't promise but I feel strongly that I've ran into odd issues like this and it was simply a speedo calibration thing..

Our 4l60 to 4l80 harness was developed on a 06 Trailblazer SS which I can't imagine having some radical difference from a 06 5.3 trailblazer. Our harness purposely ignores ISS because the 4l70 and 80 have different ISS tooth counts and at the time there was no way to correct this. We've been selling that harness for more than 10 years no and no issue. There has to be something else causing this.

[Shrek]

Never had one not lock up TCC. Prehaps you can share a file/log showing this?

It would seem that you have not done much tuning or troubleshooting with mismatched components and calibrations - for customers that are extremely picky about how their custom vehicle functions.

Over the years I have been contacted to sort similar issues as described in this thread by people who had purchased control systems from Speartech, Howell, Current Performance Wiring, PSI, and other suppliers - when a 13-pin 4L60/65 was being controlled by a T42 TCM with programming for a 15-pin 4L65/70.

Common issues included the Torque Converter not locking, or only locking under certain conditions, or only locking in certain gears. Other issues were related to DTCs and miscalculated slip - which would inhibit Cruise Control function when an E67 ECM was paired with a T42 TCM.

The bottom line is that a 13-pin 4L60/65 should work flawlessly when controlled by a T42 TCM programmed with a 13-pin 4L60/65 calibration.

[Alvin]

It would seem that you have not done much tuning or troubleshooting with mismatched components and calibrations - for customers that are extremely picky about how their custom vehicle functions.

HA!