4L65-e swap - power distribution?
Thread Starter
On The Tree
Joined: Sep 2012
Posts: 134
Likes: 0
From: New Taxes York
4L65-e swap - power distribution? Hi all,
Swapped an '06 GTO LS2\4L54-e into my '69 Camaro.
I'm having issues with the TCU communicating with both the ECU and ODBII. This seems to be causing the trans to operate in Limp Home mode.
All harnesses are from the donor car and have not been removed and replaced from either the engine or the trans... ever. I left everything where it was.
What I really need is the GTO 4L65-e wiring pin-outs for the TCU.
The wiring diagrams I have conflict with what's actually here... and seem to be for the same year Corvette, not the GTO.
The diagrams "ATC Schematics ECM,TCM Power and Ground" and "ATC Automatic Trans Controls" do not agree.
http://www.ls2.com/boggs/LS2/clutch/a4tranny08.JPG
http://www.ls2.com/boggs/LS2/clutch/a4tranny06.JPG
The ATC Power and Ground schematic shows power to the TCM as constant 12V on Pin 32 on an Orange wire. This is true... Pin 32 on my TCU is an orange wire.
It also shows Run\Start voltage on Pin 31 on a Pink\Blue wire. This is also true that Pin 31 is Pk\BU.
The Trans Controls diagram disagrees and shows Pin 31 as a BU\WH wire. There is no BU\WH wire in the TCM harness. There is however two BU wires. Neither is Pin 31.
I believe that diagram is for the Corvette only, correct?
Like I said, my scanner fails to connect to the TCM, and I get a "Lost Communications With TCU" error when reading the ECU, and the trans will not operate correctly.
I have constant 12V on Pin 32 at the TCM.
I do not have switched 12V on Pin 31.
But as I checked voltages, I was showing a constant 12V on Pin 31! I traced it to the brake light switch that I wired for the TCC signal on Pin 25 to unlock the torque convertor!! How can that possibly be since that signal is supposed to be on Pin 25?? I used these diagrams to wire it and obviously Pin 25 on the GTO TCU is something else... not TCC. The wire that I thought was Pin 25 is brown\black.
If I put my foot on the brake, the 12V went away on Pin 31 at the TCM. That's how I knew it was wired wrong.
I disconnected the brake switch wires and the 12V is no longer on Pin 31, but there is a residual voltage less than 1V, which is also present on Pin 1. I don't know what the correct signal or voltage is for Pin 1 because the ATC Controls diagram is incorrect for my trans. At least I believe it is.
That also leads me to believe I wired the TCC signal wire incorrectly. It's not really Pin 25 on this trans.
One more question...
In the other ECM,TCM Control Relays diagram, the ECM and the TCM have a yellow "Accessory" voltage signal. I assume I should have switched 12V on the yellow wire to Pin C1-18 of the ECM, which also feeds it to Pin 11 of the TCM? I trust that diagram... I think!
Could that be my issue? I do not have the ECM Pin 18 yellow wire connected to 12V.
I hope and pray I did not smoke this TCM.
Any help would be great! I'm THIS close to driving the car now.
Thanks all!
Swapped an '06 GTO LS2\4L54-e into my '69 Camaro.
I'm having issues with the TCU communicating with both the ECU and ODBII. This seems to be causing the trans to operate in Limp Home mode.
All harnesses are from the donor car and have not been removed and replaced from either the engine or the trans... ever. I left everything where it was.
What I really need is the GTO 4L65-e wiring pin-outs for the TCU.
The wiring diagrams I have conflict with what's actually here... and seem to be for the same year Corvette, not the GTO.
The diagrams "ATC Schematics ECM,TCM Power and Ground" and "ATC Automatic Trans Controls" do not agree.
http://www.ls2.com/boggs/LS2/clutch/a4tranny08.JPG
http://www.ls2.com/boggs/LS2/clutch/a4tranny06.JPG
The ATC Power and Ground schematic shows power to the TCM as constant 12V on Pin 32 on an Orange wire. This is true... Pin 32 on my TCU is an orange wire.
It also shows Run\Start voltage on Pin 31 on a Pink\Blue wire. This is also true that Pin 31 is Pk\BU.
The Trans Controls diagram disagrees and shows Pin 31 as a BU\WH wire. There is no BU\WH wire in the TCM harness. There is however two BU wires. Neither is Pin 31.
I believe that diagram is for the Corvette only, correct?
Like I said, my scanner fails to connect to the TCM, and I get a "Lost Communications With TCU" error when reading the ECU, and the trans will not operate correctly.
I have constant 12V on Pin 32 at the TCM.
I do not have switched 12V on Pin 31.
But as I checked voltages, I was showing a constant 12V on Pin 31! I traced it to the brake light switch that I wired for the TCC signal on Pin 25 to unlock the torque convertor!! How can that possibly be since that signal is supposed to be on Pin 25?? I used these diagrams to wire it and obviously Pin 25 on the GTO TCU is something else... not TCC. The wire that I thought was Pin 25 is brown\black.
If I put my foot on the brake, the 12V went away on Pin 31 at the TCM. That's how I knew it was wired wrong.
I disconnected the brake switch wires and the 12V is no longer on Pin 31, but there is a residual voltage less than 1V, which is also present on Pin 1. I don't know what the correct signal or voltage is for Pin 1 because the ATC Controls diagram is incorrect for my trans. At least I believe it is.
That also leads me to believe I wired the TCC signal wire incorrectly. It's not really Pin 25 on this trans.
One more question...
In the other ECM,TCM Control Relays diagram, the ECM and the TCM have a yellow "Accessory" voltage signal. I assume I should have switched 12V on the yellow wire to Pin C1-18 of the ECM, which also feeds it to Pin 11 of the TCM? I trust that diagram... I think!
Could that be my issue? I do not have the ECM Pin 18 yellow wire connected to 12V.
I hope and pray I did not smoke this TCM.
Any help would be great! I'm THIS close to driving the car now.
Thanks all!
Last edited by HwyStarJoe; Jul 26, 2013 at 09:06 PM.
