Desperate to solve wiring Question E38/TCM

[markeheiden]

I have been fighting a shift problem since I got my truck running. 2007 5.3 w/ 4L65E. I have an External speedo cable driven VSS that is wired per the schematic directly to pin 16 and 41 on the TCM.

The ECM schematic shows the same two wires (circuit 821 and 822) on pins 71 and 72 connecting to "transmission system".

I understand how the signal gets from the VSS to the TCM (it's wired directly to it) but there is no TCM out to ECM for the VSS???

Can anyone tell me from the attachment how the VSS signal gets to the ECM?

[LSX378]

I have been fighting a shift problem since I got my truck running. 2007 5.3 w/ 4L65E. I have an External speedo cable driven VSS that is wired per the schematic directly to pin 16 and 41 on the TCM.

The ECM schematic shows the same two wires (circuit 821 and 822) on pins 71 and 72 connecting to "transmission system".

I understand how the signal gets from the VSS to the TCM (it's wired directly to it) but there is no TCM out to ECM for the VSS???

Can anyone tell me from the attachment how the VSS signal gets to the ECM?

GM sends the speedo either via a wired connected TCM to ECM or via the GMLAN. Depends on what ECM/TCM combo you have.

[markeheiden]

No interest in a speedo signal. I only need the VSS signal to operate the transmission properly. The ECU is an E38 and the TCM is std. that comes with 2007 E38 equipped vehicles.

[LSX378]

No interest in a speedo signal. I only need the VSS signal to operate the transmission properly. The ECU is an E38 and the TCM is std. that comes with 2007 E38 equipped vehicles.

For speedo read VSS. If the TCM is not sending the VSS on the CAN and/or the ECM is not receiving it (this is optional) via hardwire or CAN then thats the glitch. It seems your year setup has no hardwire TCM > ECM, so then the TCM and the ECM need to be a matched pair.

Where is your tune from? 2007 car? truck?

[Chris@HPTuners]

TCM sends speed and other messages out on the CAN bus (GMLAN), likewise ECM sends messages to the TCM via CAN.

Chris...

[speartech]

A 2006 Yukon transmission (Gen-3) would not have the ISS that your Gen-4 setup is looking for. You should be able to just look in the connector on the transmission and see that there are no pins in positions K and V.





Also, the ISS is a digital sensor so I'm not sure there is anything to measure with an ohm meter.

If you have the vehicle driveable, after a few miles it should set a P0717.

[markeheiden]

Thanks John, I will check the pins on the trans but don't think they'll be there as you say it's a gen 3 trans. My tuner is Wayne Hartwig in WA state and after tuning and setting up the TCM and ECU in HP tuners as a 4l60e, it shifted fine in his rig.

My suspicion is a problem with my VSS or ISS but I have been able to verify all VSS wiring is in place and VSS is turning. The ISS is suspicous but Wayne's trans doesn't have one either being a 2004 4L60e?

I'll try and run it some more but it has not set any codes unfortunately.

[markeheiden]

Checked the pins and as you predicted John, no ISS in this trans. I drove it long enough to set a code and viola, P0717 as predicted!

Well done John as usual! Now what are my options to get this thing working right without spending a butt load of $$?

[waynehartwig]

Mark, you have an E38 ECM and T42 TCM

The tune on your PCM is from a 2007 Suburban 4x4 with the 5.3 and 4l60e - this is the same tune to match your engine based on the VIN you gave when I tuned it.

Mark, my setup is from an 08 Sierra 4x4 with the 5.3 and 4l60e - not 2004. It's all in an 04 Rubicon, so maybe thats where the confusion comes from?

And yes, it does shift fine in mine. The first time I had your PCM here, I was afraid of using a 4x4 tune and you wanted me to verify that the alt was charging, IIRC? So I ran your PCM and TCM in my rig for about 5 miles before pulling it and sending it all to you.


...I agree.. I hope you don't have to replace the tranny with a newer one just to get it to work.... But at least now you possibly have a reason for your problems, instead of scratching your head unknowing why....

I'll attach your tune here, in case anyone sees anything we might be able to do to 'trick' the PCM/TCM for your 2006 trans....

[LSX378]

We have a proven custom tune that does away for the input speed sensor. PM if you are interested.

[waynehartwig]

We have a proven custom tune that does away for the input speed sensor. PM if you are interested.

Yes please!

[markeheiden]

Thanks for correcting my mistaken identity on your trans. That does explain how my contollers would work in your's and not mine. I've posted my exact config. numerous times on numerous boards trying to solve this and no one (until tonight) mentioned a difference from the 07' and up (gen 4) trannies that would require something different from the 06' (gen 3) that I'm running.

It's just not that common to do the exact swap with the exact combination of parts that I am using so I totally get why it's been so hard to find. Sorry for the extra programming it's taken but I think we're finally over the hump.
Hopefully LSX378 will be able to help us out!

[waynehartwig]

Thanks for correcting my mistaken identity on your trans. That does explain how my contollers would work in your's and not mine. I've posted my exact config. numerous times on numerous boards trying to solve this and no one (until tonight) mentioned a difference from the 07' and up (gen 4) trannies that would require something different from the 06' (gen 3) that I'm running.

It's just not that common to do the exact swap with the exact combination of parts that I am using so I totally get why it's been so hard to find. Sorry for the extra programming it's taken but I think we're finally over the hump.
Hopefully LSX378 will be able to help us out!

Told ya John new his stuff And no worries on my end. I know how frustrating swaps can be....

Maybe so. Contact them directly. They emailed me, but it's a service they are willing to sell.

[speartech]

Yes, there is a work-around to make the non-ISS tranny and Gen-4 engine happy together.

[BBA]

Yes, there is a work-around to make the non-ISS tranny and Gen-4 engine happy together.

What is it? Set the speedo option to gmlan or is this one of those you have to pay to find out things?

[markeheiden]

Shouldn't HP tuners have a field for transmission year that would take into account differences like this?

[kostrizer]

I thought this might help you and save you some money.

http://www.ls1tech.com/forums/conver...-05-4l65e.html

[LSX378]

What is it? Set the speedo option to gmlan or is this one of those you have to pay to find out things?

If only it was so easy as setting speedo options .

[waynehartwig]

If only it was so easy as setting speedo options .

Really!

[BBA]

After reading that link...I think we just figured out how to solve the TBSS no speedo at WOT with a high stall converter.