LCAC_Man

iTrader: (2)

Engine, ECM, TCM is 06TBSS LS2, my 4l65e (05 Cad Escalade) does not have an ISS output, so it appears that the TCM will not buffer the raw VSS signal for output to the ECM.
Since I'm using an aftermarket Dakota Digital dash I think I can just tap into the raw VSS output for Speedo display.
Will there be any functional problems with the TCM controlling shift timing of the 4l65e using just VSS (torque management is shut off) since there is no ISS for comparison?

rsz288

Typically E40 doesnt need ISS, and your TCM wont be expecting it. The E40 should output a regular speedo signal on the speedo pin though it may need a re-tune to get right.

branndonw

iTrader: (3)

The ECM still needs a VSS signal. Without it you're going to get DTCs and it probably wont run right or shift right.

His E40 is for a TBSS. The TBSS 4L70 uses an ISS. The ISS is wired directly to the T42 TCM. The TCM requires an ISS and VSS signal to generate a buffered signal which is sent to the ECM. The ECM then generates a 4000 ppm signal and sends it to the IPC. If he uses the TBSS calibration in his E40, he will have to have an ISS signal and VSS signal going into the TCM so that the TCM will generate that buffered signal. The TBSS ECM will not accept the raw AC voltage coming directly off the VSS, so there is no way to get the VSS signal into the TBSS ECM except for the buffered signal coming from the TCM. He is probably going to have to run a GTO calibration in his ECM and TCM since the GTO tranny doesnt not use an ISS. Or he could run the TBSS calibration and just get a 4L70.

rsz288

Oops. You are right on that one. Learn something new every day. Hadnt see an E40 T42 pair with ISS before.

Yes a GTO calibration will do it. Or disable ISS.

The ISS doesnt have anything to do with speedo though, its used to achieve smoother and better matched shifts. If the TCM cal is for ISS, the shifts just wont be very civilised at times and rather unpredictable.

Doesnt the TBSS E40 take the replicated VSS feed from the T42 straight in?

branndonw

iTrader: (3)

It does in the TBSS. The TCM compares the ISS signal and the VSS signal and then generates a buffered signal based on the comparison. If you put a higher stall converter in the TBSS, when you launch, your speedo will not work until you let off the throttle. This is because the ISS signal is higher due to the increased input shaft speed, than it would normally be at that same vehicle speed. This causes the ISS vs. VSS to be out of range of what the TCM is expecting, therefor the TCM defaults to 0 and does not send out the buffered signal to the ECM. When you let off the throttle, the ISS vs VSS falls back into range and the speedo will instantly start working.

LCAC_Man

iTrader: (2)

Looks like I'm going to call my tuner and have both my ECM and TCM reflashed with an 06 GTO based tune. I'll let ya know how it works!

LCAC_Man

iTrader: (2)

Also, if anyone has the pin-outs for the 06 GTO and 06 Monte Carlo SS thottle pedals to the ecm...I need to be sure my 06 TBSS ECM reflashed to 06GTO calibration will work with an 06 MCSS throttle pedal.....man, what a mess...

branndonw

iTrader: (3)

I would almost bet money that the pedal will not be compatible with the GTO. Most of the pedals will not interchage even thought they may have the exact same pinout.

Jones'n

Wow... I guess the 5 or so swaps that we have done using the Trailblazer ECM and TCM from 05 and 06 with 4L60E transmissions shouldn't be working correctly.
That is weird that they are all working and shifting and reading the speedo just fine.
Just flash the TCM as an '05 Trailblazer.

rsz288

Are you using the TB throttle body and pedal?

Similar experience on other non ISS TCM's.

branndonw

iTrader: (3)

Only the Trailblazer SS got the 4L70 which utilizes the ISS. The 4.2 and 5.3 Trailblazers came with the 4L60 so you wouldnt have an issue if you were running the ECM/TCM from one of those. His ECM/TCM is from an SS which requires the ISS, so if he uses them without an ISS he will have problems.
He could run the 06 5.3L Trailblazer calibration though and just have it tuned accordingly, I didnt think about that.

Jones'n

I couldn't give a **** what the ISS actually does or it's purpose spelled out to such a degree... All I know is, we made LS2 Trailblazer engines using the '06 LS2 TB SS program with the pedal and all work with 4L60E transmissions that didn't have the ISS by programming the TCM as an '05 5.3.

rsz288

rofl!

branndonw

iTrader: (3)

Im was just trying to explain why the TBSS TCM will not work with his application. I never said the 5.3 calibration would not work. If you go back and reread my post you will see that I agreed with you on that.

LCAC_Man

iTrader: (2)

Engine-06TBSS LS2, Trans 05 Cad Escalade 4l65e.
OK...looks like I have a couple options:
1) Send my 06TBSS ECM/TCM in and get it reflashed to an 06 GTO configuration.
2) Send in just my 06 TBSS TCM and get it reflashed to an 05 TB 5.3 configuration.
Just to muddy the water I also will be using the 04-08 MCSS/Grand Prix/Impala throttle pedal.
What path would produce the least potential for problems??

branndonw

iTrader: (3)

Option number 2. Your pedal probably wont work with the TBSS though. Are your pedals stationary or adjustable? I have a stationary pedal for an 05 SSR that I know for a fact works with my 08 TBSS if your MC pedal doesn't work.

LCAC_Man

iTrader: (2)

I've got the original TBSS pedal but it's pretty cheesy and the mounting for it sucks for my application, the MCSS pedal bolts up nice to the firewall right where the original jeep pedal was...

LCAC_Man

iTrader: (2)

Do you have a pic of this...on how it bolts up??

branndonw

iTrader: (3)

LCAC_Man

iTrader: (2)

Yeah, that one mounts up the same as the TBSS pedal, I'm gonna talk with Jesse at Wait4Me and see if this MCSS pedal can be made to work...worse case is that I'll have to fab up a bracket and use the orig TBSS pedal that I have...