Can't read vehicle speed, whats wrong? Please help

[ccrane0044]

Hey guys, I recently swapped an LS3 into my Cutlass to replace the LY6 that let go on me on boxing day (Merry Christmas right...). The transmission that was matched to the LY6 is a 6L90e, and I am using the same transmission with the LS3 as well.

When I purchased the LS3 I was told it was cammed so I got the ECM with it so that I wouldn't have to worry about messing up the tuning for the engine (my tuning skills are limited). My plan was to delete the VATS, change the transmission tuning since it was a stick shift car and hoped everything would be fine. But... I'm not that lucky. I can't seem to read the vehicle speed therefore my transmission will not shift out of first gear. For the Speedo Calibration section I just copied the settings I had from my original tune which worked perfectly but it doesn't work at all with the new ECM.

I'm hoping someone can help me out in regards to explaining how I should set things so that I can read vehicle speed correctly so my transmission can shift. Attached is the original tune from the LS3 ECM, my altered version for the VATS delete and the transmission tuning and the Tune I had previously to installing the LS3 which was with the LY6 ECM.

This is also my daily driver so any help to get this working asap is greatly appreciated.

[* _ *]

You might need to integrate a tcm that not only has the ability to control the xmission but also to what hpt supports.

Once that is figured out, you should be safe to pull in a pcm file and tcm file should you not have the desire to trial and error tuning it yourself.
VATS seems like a dead function. Im not sure what purpose such features like that serve if it "might" or "might not" work. SKIM is another one..

[ccrane0044]

You might need to integrate a tcm that not only has the ability to control the xmission but also to what hpt supports.

Once that is figured out, you should be safe to pull in a pcm file and tcm file should you not have the desire to trial and error tuning it yourself.
VATS seems like a dead function. Im not sure what purpose such features like that serve if it "might" or "might not" work. SKIM is another one..

Sorry, I don't understand what you mean by this at all. is it possible to elaborate?

[Ben C]

I would be saving the tune off the pcm you purchased, going back to original pcm and copying over differences to suit the new engine. Won't cost credits and the transmission will work
you cant just put In a manual pcm and expect the transmission to work
using original pcm would be easiest.

[ccrane0044]

I would be saving the tune off the pcm you purchased, going back to original pcm and copying over differences to suit the new engine. Won't cost credits and the transmission will work
you cant just put In a manual pcm and expect the transmission to work
using original pcm would be easiest.

I already purchased the licence for the new ECM so that's not an issue. I tried copying over the data to the old ECM which made it so that the transmission works but the engine didn't run well at all.

[ccrane0044]

I would be saving the tune off the pcm you purchased, going back to original pcm and copying over differences to suit the new engine. Won't cost credits and the transmission will work
you cant just put In a manual pcm and expect the transmission to work
using original pcm would be easiest.

The ECM has the option to select a manual or Automatic transmission. Would that not mean that it can work with whichever type of transmission you choose and then that speaks to the Valvebody TCM that is in the 6L90e?

[ccrane0044]

Now it seems like my idea to use my original ECM that cam with the 6L90e isn't an option. Every time I try to write a new tune to my original ECM I get this message... "Controller unlocker: x36 exceeds number of attempts". I am not able to make any changes at all to that ECM nor can I rear any information that is on it. Along with that the LS3 ECM isn't reading vehicle speed so that one is useless to me as well.

[ccrane0044]

Does anyone know if Pin #18 in the J1 connector may be my issue?

In the pinout instructions for the LY6 harness it states to remove that pin, in the LS3 pinout instructions they state that it "May be required" for 6L80e transmissions. It is a "Accessory Wakeup Serial Data pin for +12V key hot signal.

All pinout instructions were found on lt1swap.com

Attachment 76480

[5FDP]

The ECM has the option to select a manual or Automatic transmission. Would that not mean that it can work with whichever type of transmission you choose and then that speaks to the Valvebody TCM that is in the 6L90e?

It may have the option to switch but that computer was never programmed to run a TCM, so it won't speak with it. Also the truck TCM calibration would be much different than the car calibration.

[ccrane0044]

It may have the option to switch but that computer was never programmed to run a TCM, so it won't speak with it. Also the truck TCM calibration would be much different than the car calibration.

I figured that was one of the things that HP tuners can do, is reprogram the ECM and TCM to be able to operate both. That's why there's a Manuel and Automatic option. Unless I'm completely mistaken?

As for the TCM calibration, one of the first things I did when I initially did my swap was change the calibration in the TCM to a CTS-V transmission tune, or at least close to it. The truck tune was not very enjoyable to drive.

[ccrane0044]

What I'm afraid of now is that I corrupted my original ECM from the LY6, I was able to read vehicle speed from that ECM and everything worked fine, I just needed to make some adjustments to the tune but now I receive the Controller unlocker message. So now I have one ECM that I licences which is now corrupted, and another that I also purchased a licence for which doesn't work with my transmission. And I have no idea what I should do next in regards to getting a new ECM and if I have to go that route then which one should I get?