TBSS / Envoy 6.2 6L80 erratic speedo 0 to 158

[madkidd007]

Short background I acquired a 2008 envoy denali 5.3 2wd as a roller. No motor or trans parts, factory ECM and TCM came with it.
I swapped in a 6.2 from an 07 escalade with a factory LS3 camshaft, so far seems to run pretty good being its very close to a TBSS LS2(will dial it in after the current issue is resolved)

Here is where the fun starts, using a 6L80 and T43 Techm from a 2007 escalade which has the same OS as a 2008.
The issue is no speedo on the cluster no matter what I do, but the VCM scanner jumps back and forth from actual speed to 158.
Truck will shift and drive down the road under light throttle, but if you give it medium to heavy throttle it cant make up its mind what to do assuming because of the VSS.

The trans is wired just like in my lincoln which i drive everyday, Can wires 10/11 from the trans are tied to 2 pair that went to the original T42 (pins 6/7 and 37/38) From the TBSS forum you need to tie into both pair, when I was tied into only 37/38 the VCM editor would not recognize the T43 and gave a detect protocol error.

From all my research I should have compatible Operating Systems and years.
Side note i have a friend with a 6l80 in his 08 which works perfectly(same speedo settings) but he used the TrueBlueMotorsport interface module, I would like to avoid using anything aftermarket as this is for my wife to daily drive.
Also running the factory neutral safety from the 4l60 with a custom shift shaft so the chassis knows when its in park/neutral/reverse/drive

Any insight would me much appreciated.
attaching a short log and my tune file for reference08 envoy denali 6.2 motor and trans after first drive.hptenvoy erratic speedo jumping to 158.hpl

[blindsquirrel]

Trouble Codes:
P0606 - ECM / PCM Processor (Current)

And nope, it's not because of ETC tables being changed, they are stock according to TIS.

[madkidd007]

And nope, it's not because of ETC tables being changed, they are stock according to TIS.

first off thank you, truely.
second, how the hell did you see that code, nothing comes up when i look

I specifically copied everthing from an 08 TBSS, except throttle to try and avoid issues.

[blindsquirrel]

Attachment 154753

[blindsquirrel]

Also, note that '158 MPH' is what it defaults to when there is no comms between ECM & TCM. Maybe just a coincidence but with nothing else sticking out I'd look real close for intermittents in the CAN wiring.

But only after figuring out what's causing the P0606. Do that first.

[madkidd007]

Also, note that '158 MPH' is what it defaults to when there is no comms between ECM & TCM. Maybe just a coincidence but with nothing else sticking out I'd look real close for intermittents in the CAN wiring.

But only after figuring out what's causing the P0606. Do that first.

never thought to take a look there, always looked while connected. no check engine lights have come up either. with that said its the first time ive seen that pop up since having everthing connected.
It was bugging me so I ended up just doing a segment swap with my buddy's file I had from his 08 and wouldnt you know, now I have correct speed readings in the ECM.

Nothing on the cluster still, but i believe that may be a wiring work around. I am going to turn off every code and max out all the settings in the original T42 and add it into the system, so in theory it isnt sending commands out and/or see an error and tell the ECM to go into reduced power. Wont know if it pisses off the truck till I try it, but that will be a tomorrow thing.

If I get this figured out then as far as I know itll be the first GMT360 platform to have every function working correctly with no outside modules or adapters. Which is my number one goal, well number one is not ever having my wife ask why something doesnt work.08 envoy denali 6.2 motor and trans with kelvin segments.hptenvoy with kelvins 6l80 swap segments no cluster speed.hpl

[madkidd007]

Update:
T42 is not wired up anymore and the vehicle is 99 percent working.
Speed is working in the scanner, although it seems to jump a couple MPH when watching it going down the road.
PRNDL, reverse lights, daytime running lights, everything is working like stock.

Only issue still have no speed on the cluster, going to see if I can use my friends known good cluster.

hey squirrel i dont know what year your TBSS is but if its gen4 bypass the 4L80 option. Not foot braking, just stabbing it from a stop and the 0-60 is 5.8 seconds with bad tires, 2WD, stock stall,Attachment 15480708 envoy denali 6.2 motor and trans with kelvin segments.hptenvoy 6.2 E67 6L80E T43 first drive, unstable speedometer.hpl and 3.73 gears

[blindsquirrel]

Mine's a 2WD Envoy, and it's an '06, so E40, and there's no (reasonable) way to get a T43 to talk to the Gen-3-but-integrated-TAC ECM. There is/was some aftermarket company working on an interface/translator box doohickey but it was going to be way too much money so I stopped paying attention. I don't like solutions like that anyway (the add-on box thing).

[precisionpartsource]

Update:
T42 is not wired up anymore and the vehicle is 99 percent working.
Speed is working in the scanner, although it seems to jump a couple MPH when watching it going down the road.
PRNDL, reverse lights, daytime running lights, everything is working like stock.

Only issue still have no speed on the cluster, going to see if I can use my friends known good cluster.

hey squirrel i dont know what year your TBSS is but if its gen4 bypass the 4L80 option. Not foot braking, just stabbing it from a stop and the 0-60 is 5.8 seconds with bad tires, 2WD, stock stall,Attachment 15480708 envoy denali 6.2 motor and trans with kelvin segments.hptenvoy 6.2 E67 6L80E T43 first drive, unstable speedometer.hpl and 3.73 gears

The Speedometer issue is an easy fix, under the speedometer tab switch the source from calibration to GMlan. How did you get the gear position to read? I have park and neutral by grounding the pnp wire. I've tried everything i can think of and have had no luck for 2 months now.... HPT reads everything and seems fine, the only dtc i get is lost communication with bcm from the transmission. I might try to swap some transmission segments from yours and see what happens. Let me know!

[precisionpartsource]

Also, note that '158 MPH' is what it defaults to when there is no comms between ECM & TCM. Maybe just a coincidence but with nothing else sticking out I'd look real close for intermittents in the CAN wiring.

But only after figuring out what's causing the P0606. Do that first.

I had an intermittent p0606 also at first, it turned out to be a loose ground which actually explains the crazy speedo readings as well. I tried the segment swapping from yours and mine is the same as always... it just gives me a park and neutral signal but no forward or reverse gear selections. the prnd321 shows invalid in hpt

[madkidd007]

I had an intermittent p0606 also at first, it turned out to be a loose ground which actually explains the crazy speedo readings as well. I tried the segment swapping from yours and mine is the same as always... it just gives me a park and neutral signal but no forward or reverse gear selections. the prnd321 shows invalid in hpt

My speedo issue wasnt as simple as you suggested. It was erratic, not non functioning.
Long story short, My PRNDL, reverse lights, daytime running, etc all work since the CANBUS communicates those functions.
If youre having a communication issue then you most likely need to add in a termination resistor to the CAN circuits.

With these segments in the trans, and both pair of CAN wires at the T42 now tied together with the T43, as well a factory termination resistor from a tahoe, all communications funtion.

I do still have one issue to address. When i pull it into the gear selection below drive I am not getting a different shift mode like in my lincoln.
My lincoln is a 2013 and this is a 2008 OS so im having to do my research08 envoy denali 6.2 motor and trans with kelvin segments.hpt

[blindsquirrel]

Not all OSes will do TUTD, even if your file has all the settings for it and no matter how you set it up. Same as how not all OSes will do flex fuel even though the settings are there, not all OSes will do PWM fans, etc.

[madkidd007]

Not all OSes will do TUTD, even if your file has all the settings for it and no matter how you set it up. Same as how not all OSes will do flex fuel even though the settings are there, not all OSes will do PWM fans, etc.

Not referring to TuTd, although I know this one will because we have it functioning in my buddys truck.

Talking about when you pull the shifter into what would be 3rd on a 4 speed. In my lincoln it is all setup as a 2013 vette, and in my other friends body swapped 08 G8 GT, I have them both setup when you pull it down you have a different shift pattern and it holds the gear longer so it doesnt short shift under light throttle.

[blindsquirrel]

OK, so subtract 'TUTD' and replace with 'feature'. A thing that one platform/OS will do is not guaranteed to be able to be added or enabled on some other different platform/OS.

[madkidd007]

OK, so subtract 'TUTD' and replace with 'feature'. A thing that one platform/OS will do is not guaranteed to be able to be added or enabled on some other different platform/OS.

Well that's just the thing, my buddy's 9-7x is also an 08 so same year and platform. I need to get him to come by so I can pull just his TCM file. First I need to confirm it has the second shift pattern function. I've driven it countless times but every time i pulled it down i would go into TuTd to do a pull so I guess I'm on hold till I can get him to come over

[precisionpartsource]

My speedo issue wasnt as simple as you suggested. It was erratic, not non functioning.
Long story short, My PRNDL, reverse lights, daytime running, etc all work since the CANBUS communicates those functions.
If youre having a communication issue then you most likely need to add in a termination resistor to the CAN circuits.

With these segments in the trans, and both pair of CAN wires at the T42 now tied together with the T43, as well a factory termination resistor from a tahoe, all communications funtion.

I do still have one issue to address. When i pull it into the gear selection below drive I am not getting a different shift mode like in my lincoln.
My lincoln is a 2013 and this is a 2008 OS so im having to do my research08 envoy denali 6.2 motor and trans with kelvin segments.hpt

I finally got mine working, The Tehcm had some internal problems even though it was a reman. i replaced it with another used one and everything works! as far as the speedo reading on the dash everyone on the tbss forum was saying to make sure to select the source as "GM Lan" instead of calibration. Im unsure on it being erratic though. this is the forum i was referencing https://www.tbssowners.com/threads/6...h-ease.243080/ and its toward the end where people are talking about the calibration changes to get the speedo working.