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6l80e stuck in 3rd

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Old Mar 23, 2011 | 05:24 AM
  #1  
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Default 6l80e stuck in 3rd

Does anyone have experience with conversions using 6l80e that can shed some light on my problem. I have only just got the car running and it will only select 3rd gear

Car is a 68 camaro with l76 engine and 6l80e from holden commodore(g8).

The trans comes up with a p0602 fault code pcm programming error and when a tech 2 is plugged in the diagnostics screen says to use sps to program the ecu before continuing.

The e38 (2010) pcm always reads 158mph(255kph) but i don't know if this is an issue because i also have an (07-08) pcm that when plugging in doesn't show this fault, but both e38s will not give a signal out on the vss output or the tach output.

the tuner that i am using says the trans has accepted a read and write using hptuners but i am unsure if this trans ecm needs to have an initial tis program installed to make it work correctly, or if a mismatch of operating systems could be the fault, do the operating systems ie tran and engine need to match and have the same vin no?

I did notice that the trans does not show a vin no when looking at the calibration info is this normal?

Anyone that could help with this would be appreciated

thanks
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Old Mar 23, 2011 | 12:06 PM
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If you are reading 158mph you have the same problem a lot of us have with the E38's. You are not getting a proper speed input from the tcu to the ecm. On my wiring diagram for a G8 it showed the signal going through the body control module. The speed signal is converted to be sent over the GMLan. Your trans will not work properly if the engine thinks it is going 158mph all the time.
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Old Mar 23, 2011 | 03:10 PM
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Originally Posted by buddyholly
If you are reading 158mph you have the same problem a lot of us have with the E38's. You are not getting a proper speed input from the tcu to the ecm. On my wiring diagram for a G8 it showed the signal going through the body control module. The speed signal is converted to be sent over the GMLan. Your trans will not work properly if the engine thinks it is going 158mph all the time.
Thanks for your info how have others go around the pcm showing 158mph I thought that the trans has an ouput speed sensor that the tcm would send to the pcm on gmlan. I wonder whether using a different calibration from say a corvette or such would send the vss info differently.
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Old Mar 24, 2011 | 08:39 PM
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The VSS run through the TCU and one would think go from there to the ECU. My reading of the G8 wiring diagram has it going through the BCU before the speed signal gets to the ECU, but that has been a while since I poured through the diagrams.
Check out this thread.
http://www.hptuners.com/forum/showth...t=26404&page=3
Kmkomes post towards the bottom are the only real test to see what it takes to convert the vss signal directly to a speed signal over the GMLan. This is getting to be a pretty common problem so I hope someone is able to come up with a solution.
Hope this helps a bit...keep us posted, lots of people would like to see the 6l90e's running. A few of them are running around but getting them to live with the clutch to clutch shift is very tricky it seems...
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Old Mar 24, 2011 | 08:57 PM
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I have a 6L80E out of a truck. Gentleman who built my harness, had me remove the TCU and send it to him to download Corvette shift program as vette doesn't go thru BM. Make it easy to rig up TU/TD shifter, momentary contact switch(s), or Paddles to manual shift.

Most of the people I know all run the corvette shift program too and have no problems.

Maybe soon I'll find out if I will.
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Old Mar 24, 2011 | 11:51 PM
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Originally Posted by 68sstt
Does anyone have experience with conversions using 6l80e that can shed some light on my problem. I have only just got the car running and it will only select 3rd gear

Car is a 68 camaro with l76 engine and 6l80e from holden commodore(g8).

The trans comes up with a p0602 fault code pcm programming error and when a tech 2 is plugged in the diagnostics screen says to use sps to program the ecu before continuing.

The e38 (2010) pcm always reads 158mph(255kph) but i don't know if this is an issue because i also have an (07-08) pcm that when plugging in doesn't show this fault, but both e38s will not give a signal out on the vss output or the tach output.

the tuner that i am using says the trans has accepted a read and write using hptuners but i am unsure if this trans ecm needs to have an initial tis program installed to make it work correctly, or if a mismatch of operating systems could be the fault, do the operating systems ie tran and engine need to match and have the same vin no?

I did notice that the trans does not show a vin no when looking at the calibration info is this normal?

Anyone that could help with this would be appreciated

thanks
Per the emails 68sstt, P0602 means the trans still has the factory test stand program running in it. Most tuners dont get any time on these issues. Simply reading the flash out and then reflashing just retains the test stand program.

It needs an SPS flash with a regular production car calibration based on an applicable VIN. But dont use a 2010 VIN, that will probably fritz the TCM. Preferably a local 08 VIN.

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Old Sep 30, 2012 | 04:18 AM
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I am running an 06 Vette LS2 motor with a 2011 6l80e in my 69 Firebird, the TRANS only runs in limp mode (3rd gear) so it seems that the ECM and TCM are not communicating. I'm told that I need to flash the system, I live in Houston Tx and have not been able to find anyone that can flash my system locally in Houston, the GM dealer refuses to do this so does anyone know where I can have it flashed in Houston?
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Old Oct 1, 2012 | 09:53 AM
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Originally Posted by Fine69
I am running an 06 Vette LS2 motor with a 2011 6l80e in my 69 Firebird, the TRANS only runs in limp mode (3rd gear) so it seems that the ECM and TCM are not communicating. I'm told that I need to flash the system, I live in Houston Tx and have not been able to find anyone that can flash my system locally in Houston, the GM dealer refuses to do this so does anyone know where I can have it flashed in Houston?
Who did your wiring harness?

Apart from that, a 06 ECM cant be flashed up to an 11 version, and an 11 trans cant be flashed down to an 06 TCM.

Without killing them that is.

You need an 11 ECM, or an 06 TCM.

Though it maybe more than just a mismatch on ECM TCM.
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Old Dec 30, 2012 | 08:04 AM
  #9  
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Originally Posted by rsz288
who did your wiring harness?

Apart from that, a 06 ecm cant be flashed up to an 11 version, and an 11 trans cant be flashed down to an 06 tcm.

Without killing them that is.

You need an 11 ecm, or an 06 tcm.

Though it maybe more than just a mismatch on ecm tcm.

i did install a brand new flashed 2010-2011 e38 ecm in the 69

firebird and ended up with the exact same results, strictly

operates in limp mode only with the 6l80e, i have been trying to

locate a harness wiring diagram to double check the harness that

was built locally, so far everything looks to be correct but that

is using limited diagram resources.
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Old Dec 30, 2012 | 10:38 AM
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Hey guys,
I had a similar limp mode 3rd gear only problem.
But my dtc was different so it probably wont help you guys.

But here's a link to my previous thread including solution.

https://ls1tech.com/forums/conversio...dtc-p2534.html

Mine turned out to be how the ECU versus the TCM power on timing.
Basically, the ECU is wired direct to the ignition, but the TCM should be powered by the ECU controlled Main Relay. Since the ECU stays on briefly after key off, this setup allows the TCM to stay on as well.

Good luck.
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Old Dec 30, 2012 | 12:20 PM
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I hope I don't have this problem. I am using a slightly modified factory harness out of a 2009 Escalade for my L92/6L80econversion. So I have the Power Train Relay and Run/Crank Relay wired in as per the factory diagrams. No BCM and the 120ohm resistor at the the diagnostic terminal. Also fused battery power to the ECM and transmission as per the factory diagrams.
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