4L60 speed sensor wiring?
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From: San Antonio
4L60 speed sensor wiring? I have a 2000 Camaro that came with a 4L60. I need to find the wire that goes from the transmission speed sensor to the speedometer. It's basically the speed signal wire that I need to find. My transmission wire harness has 2 small connectors, and 1 big connector. I need to connect my new (6L80) transmission wire harness to the speed signal wire on my car to make the speedometer work. I figured it would be easier to get to the wire harness under the car, rather than take the dash apart.
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From: San Antonio
So, that’s pin 50 of the red PCM connector, right?
Is that the input signal or the output signal wire? I would need the input signal wire. The PCM should give my speedometer the correct speed once I give the PCM the transmission output speed. So basically, the transmission output goes to the PCM input.
Is that the input signal or the output signal wire? I would need the input signal wire. The PCM should give my speedometer the correct speed once I give the PCM the transmission output speed. So basically, the transmission output goes to the PCM input.
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From: San Antonio
What about pins 20 and 21? Those appear to be VSS signals high and low. Do those go into the PCM from the transmission? That’s basically the “side” of the PCM I need to tie into. I need to give the PCM a transmission speed signal. Once it has the transmission speed, it will send the correct signal to the speedometer through one of the other wires.
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I don’t have a rear speed sensor anymore. I have a 6L80 now. The transmission harness I bought provides the speed signal. I just needed to know which PCM wire to splice it too. I think pin 20 or 21 will work. I’ll try a temporary splice before I cut any wires and make it permanent.
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From: San Antonio
Well, pin #21 didn't work. I guess I'll try the others until I find one that works. It shouldn't need a ground if it's just a signal, right? The TCM/harness is grounded, and all other signal wires are working without any "extra" grounds.
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From: Ann Arbor, MI
This thread explains the problem and suggests some solutions:
https://67-72chevytrucks.com/vboard/...d.php?t=509662
In short the only signals from/to a 6L80E are on the digital CANBUS; kinda like the network wire to your computer. So you cannot just tap into it; you need another computer to decode it, like an ECU or BCM. According to that thread a typical ECU does not have a speedometer output signal, only a compatible BCM does.
What ECU are you using to connect to the 6L80E?
Perhaps someone has made a simple computer module to listen on the CANBUS and read the vehicle speed from it. More info on decoding the GM CANBUS is here: https://pcmhacking.net/forums/viewtopic.php?t=7113
https://67-72chevytrucks.com/vboard/...d.php?t=509662
In short the only signals from/to a 6L80E are on the digital CANBUS; kinda like the network wire to your computer. So you cannot just tap into it; you need another computer to decode it, like an ECU or BCM. According to that thread a typical ECU does not have a speedometer output signal, only a compatible BCM does.
What ECU are you using to connect to the 6L80E?
Perhaps someone has made a simple computer module to listen on the CANBUS and read the vehicle speed from it. More info on decoding the GM CANBUS is here: https://pcmhacking.net/forums/viewtopic.php?t=7113
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From: San Antonio
My car doesn't have CANBUS. I am using the TCM-2600 Harness from Zero Gravity. It is connected to the 6L80, and appears to be working as advertised. I just don't have any speed indication in the car. Zero Gravity suggested splicing their "speed output" wire to my PCM (red) pin #21. I tried that, and still don't have speed indication.
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I'm thinking (hoping) that maybe the TCM-2600 does all the signal converting internally, and sends it out ready to be used by the speedometer. Perhaps connecting the TCM-2600 to pin #50 would make the speedo work (as previously suggested). I'll try that next, and report back.
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From: Ann Arbor, MI
Pin 50 on the PCM is an output signal. You should never connect two output signal together as one device could then burn out the other. However, it will be fine to connect your TCM-2600 output to whatever Pin 50 is connected to, presumably your speedometer, as long as the connection to pin 50 is cut.
Sorry for the confusion from my previous post - between moderating "Conversions and swap" and other areas, I've been looking at CANBUS solutions lately and overlooked that you had a 2000 PCM even though I had days earlier studied Mr. Bond's diagram.
Sorry for the confusion from my previous post - between moderating "Conversions and swap" and other areas, I've been looking at CANBUS solutions lately and overlooked that you had a 2000 PCM even though I had days earlier studied Mr. Bond's diagram.
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From: Poplarville, MS
Yes, you are correct. Your car does not have CANBUS but your 6L80 trans TCM does use CANBUS.
I looked up what the TCM-2600 is. It is a transmission control module and harness. You may be able to disconnect pin 50 at the engine PCM and connect the speed signal wire from the TCM-2600 module to pin 50, dark green/ white wire as dixiebandit69 said in post 2.
If this doesn't work, you may try contacting Dakota Digital. They probably have some short for module that will get these modules to play nice together.
Does the engine PCM show a vehicle speed when accessed with a scanner? Does cruise control work?
I looked up what the TCM-2600 is. It is a transmission control module and harness. You may be able to disconnect pin 50 at the engine PCM and connect the speed signal wire from the TCM-2600 module to pin 50, dark green/ white wire as dixiebandit69 said in post 2.
If this doesn't work, you may try contacting Dakota Digital. They probably have some short for module that will get these modules to play nice together.
Does the engine PCM show a vehicle speed when accessed with a scanner? Does cruise control work?
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From: Nitro Alley
If terminologically using "CANBUS" as such...
Than no Vehicles have it.
It is the Protocol in which Control Modules communicate with one another via Data-Lines through-out a Network.
Either a group of Control Modules use CANBUS (Such as GMLAN) or do Not.
If you have a Vehicle with a 6L80E/ 6L90E Transmission...
Than CANBUS is being used; as the TECHM in that Transmission will ONLY operate using the GMLAN Protocol to other Control Modules.
Many of you guys will also be using the the GM TCM2650 "Control Module Interface" to communicate with any and all other Control Modules for your "Swap-Projects".
The GM TCM2650 is NOT actually a TCM, but Only an Interface for the Actual Control Module-Valve Body Assembly (TECHM).
This Interface serves as a point of Interconnect to the ECM, EBTCM, TCSCM, ASCM, SDM, VCIM and some select few other Control Modules that are reserved for the "High-Speed" Portion of the GMLAN System.
They are all part of a critical network that protects the Driver and any other Vehicle Occupants.
The Several Dozen other Control Modules are Relegated to the "Low-Speed" Portion of the GMLAN System.
Than no Vehicles have it.
It is the Protocol in which Control Modules communicate with one another via Data-Lines through-out a Network.
Either a group of Control Modules use CANBUS (Such as GMLAN) or do Not.
If you have a Vehicle with a 6L80E/ 6L90E Transmission...
Than CANBUS is being used; as the TECHM in that Transmission will ONLY operate using the GMLAN Protocol to other Control Modules.
Many of you guys will also be using the the GM TCM2650 "Control Module Interface" to communicate with any and all other Control Modules for your "Swap-Projects".
The GM TCM2650 is NOT actually a TCM, but Only an Interface for the Actual Control Module-Valve Body Assembly (TECHM).
This Interface serves as a point of Interconnect to the ECM, EBTCM, TCSCM, ASCM, SDM, VCIM and some select few other Control Modules that are reserved for the "High-Speed" Portion of the GMLAN System.
They are all part of a critical network that protects the Driver and any other Vehicle Occupants.
The Several Dozen other Control Modules are Relegated to the "Low-Speed" Portion of the GMLAN System.
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From: San Antonio
Pin 50 on the PCM is an output signal. You should never connect two output signal together as one device could then burn out the other. However, it will be fine to connect your TCM-2600 output to whatever Pin 50 is connected to, presumably your speedometer, as long as the connection to pin 50 is cut.
Any ideas of what I did wrong here?
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So, it turns out that my battery was dead. I seem to have a parasitic drawl. I'll work on that next. I charged the battery back up, and I was driving the car around this morning. The pin 50 wire does seem to be the correct wire to make the speedo work. I need to do some calibrating though. At 25 mph, the speedo is reading about 150 mph. I'll update my original "build" thread.