New Torque convertor now ECM Wont Communicate

68jay · Jul 4, 2024

Hoping someone can shed some new light...Long Story short I have a 2017 Tahoe, transmission started slipping in 1-3 gear, took it out and apart. Everything I checked was in good shape (ie Clutchs/bearings etc.) I replaced the Torque Converter and reinstalled everything back in..

As always I had the battery disconnected in all this but when I hooked it back up seemed to be at only 5 volts..not sure how..recharged and tested battery everything was fine..

Truck dash lights up gives me a bunch of warnings about steering, stabilizer etc but will not start and then gives me a warning that its "not in park"? Checked everything to make sure including opening up the pan and physically checking and including replacing the "Shift Indicator switch" on the TECHM but still gives me the "Action Notice".

Hooked up my scanner and tells me "Error" and cannot even read my ECM (Fuses etc all fine)..I have chased my tail with double checking everything but have been defeated.

Any new ideas would be helpful!

NickTransmissions · Jul 4, 2024

68jay said:
Hoping someone can shed some new light...Long Story short I have a 2017 Tahoe, transmission started slipping in 1-3 gear, took it out and apart. Everything I checked was in good shape (ie Clutchs/bearings etc.) I replaced the Torque Converter and reinstalled everything back in..

As always I had the battery disconnected in all this but when I hooked it back up seemed to be at only 5 volts..not sure how..recharged and tested battery everything was fine..

Truck dash lights up gives me a bunch of warnings about steering, stabilizer etc but will not start and then gives me a warning that its "not in park"? Checked everything to make sure including opening up the pan and physically checking and including replacing the "Shift Indicator switch" on the TECHM but still gives me the "Action Notice".

Hooked up my scanner and tells me "Error" and cannot even read my ECM (Fuses etc all fine)..I have chased my tail with double checking everything but have been defeated.

Any new ideas would be helpful!

Idea #1 - change your thread title, put something that indicates your specific problem

Idea #2 - Perform a Fast adapt relearn - must be done before you attempt to drive it.

Idea #3 - Read through my thread on these transmissions, you may find your answers, including your IMS concern, there.

GM 6L80 Transmission Information Thread

Hi All, Since so many of us own at least one Tahoe or Yukon equipped with a 6L80, I figured I'd start an all-encompassing transmission thread with videos, links and other information as it relates to the 6L80/90 transmissions. I'll get it going with a tear down and inspection video and go from...

www.tahoeyukonforum.com

OR VietVet · Jul 4, 2024

Well, since it sounds like you did not have the problem before the work, you gotta do your due diligence and reinspect the work and connections you did.

68jay · Jul 5, 2024

NickTransmissions said:
Idea #1 - change your thread title, put something that indicates your specific problem

Idea #2 - Perform a Fast adapt relearn - must be done before you attempt to drive it.

Idea #3 - Read through my thread on these transmissions, you may find your answers, including your IMS concern, there.

GM 6L80 Transmission Information Thread

Hi All, Since so many of us own at least one Tahoe or Yukon equipped with a 6L80, I figured I'd start an all-encompassing transmission thread with videos, links and other information as it relates to the 6L80/90 transmissions. I'll get it going with a tear down and inspection video and go from...

www.tahoeyukonforum.com

Thanks I will read through...and Edited my title..

91RS · Jul 5, 2024

Make sure the transmission connector is plugged in. The ECM if after the TCM in the network.

NickTransmissions · Jul 5, 2024

68jay said:
Thanks I will read through...and Edited my title..

Rgr...Have you attempted to reestablish communication and re-set the adapts to factory new using your scan tool?

68jay · Jul 6, 2024

I don’t have a scan tool that can reset, I have checked tge connection on the transmission 3 times to ensure.. starting to think it could be the BCM?

One thing I should also note is something is draining the battery, I have recharged and load tested and the battery is good, I also left it all night unplugged from the truck and had kept a charge.

NickTransmissions · Jul 6, 2024

68jay said:
I don’t have a scan tool that can reset, I have checked tge connection on the transmission 3 times to ensure.. starting to think it could be the BCM?

You have to do a fast adapt relearn anytime you do anything to the transmission beyond just a fluid and filter change. This includes the torque converter since the computer will adapt to TC degradation that shows up as drivability symptoms and/or anomalous data readings to the PCM. So you will need to acquire a scan tool that's capable of doing so...Besides, this is an excellent opportunity for you to augment your kit with a scanner since every DYI'er shouldn't be without one, especially those that own computer-controlled vehicles (early 1980s+).

I'd go over everything in the transmission area again, just to be sure no ground wires/straps are missing/loose, no wires are cut/frayed, everything is connected/plugged in, etc.

68jay · Jul 6, 2024

If there is already a communication “error” in my scanner, will the adapt scanner work?

Fless · Jul 6, 2024

Is your scanner able to communicate with ANY modules?

New Torque convertor now ECM Wont Communicate

68jay

TYF Newbie

NickTransmissions

Sin City

GM 6L80 Transmission Information Thread

OR VietVet

Multnomah Falls

68jay

TYF Newbie

GM 6L80 Transmission Information Thread

91RS

Full Access Member

NickTransmissions

Sin City

68jay

TYF Newbie

NickTransmissions

Sin City

68jay

TYF Newbie

Fless

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