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'08 CTS V8 swap

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Discussion starter · #102 ·
Trying to get this TCM mounted somewhere and I’m thinking about putting it in the back right corner by the ECM on the firewall. Only issue Is these 2 connections coming off the the same section of the harness the TCM plug is on. Looking to get some insight on what they are for.
The smaller connector has 2 light green wires
 
#103 ·
R_shum said:
Trying to get this TCM mounted somewhere and I’m thinking about putting it in the back right corner by the ECM on the firewall. Only issue Is these 2 connections coming off the the same section of the harness the TCM plug is on. Looking to get some insight on what they are for.
View attachment 625824
The smaller connector has 2 light green wires
Click to expand...
you might need to split the loom and see where they go. Or use an ohm meter…
 
#104 · (Edited)
Big_kid said:
can you supply pinout diagram for TCM
Click to expand...
Here ya go...
For Gas van... They apparently had a Diesel as well.


Image


I have attached the connector end printouts for both vehicles for ALL of the connectors. This should be helpful for this project and I am sure other people can make use of the pinouts for the CTS as the pinouts for the 2008 are pretty close for all of the 2008-2013 sedans. And for same components on Wagon and probably Coup as well. Although the Wagon and Coup have other stuff not included since they were both introduced in 2010 and my stuff only goes to 2009.
 

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#105 ·
PIN 26 from the fuse box will go to PIN 11 on the TCM
this is the 12v signal from the fuse box to “wake up” the TCM module.
it’s a dark blue wire circuit number 5985
 
#106 ·
R_shum said:
Only issue Is these 2 connections coming off the the same section of the harness the TCM plug is on. Looking to get some insight on what they are for.
View attachment 625824
The smaller connector has 2 light green wires
Click to expand...
i found these connectors that RHR supplied for us.
the 6 wire connector is for the blower motor and the two wire is for A/C low pressure cut out.
you can delete these wires.
 
Discussion starter · #107 ·
Big_kid said:
i found these connectors that RHR supplied for us.
the 6 wire connector is for the blower motor and the two wire is for A/C low pressure cut out.
you can delete these wires.

View attachment 625837 View attachment 625838
Click to expand...
Sweet! I’ll get these eliminated and out of the way.

I’ve managed to make some more progress in the fuse box. Just need to run a few more ABS wires and a couple other misc wires. This leads into my questions …Pin 10 for X101. This is for the fuel level sensor that teminates into pin 70 on J1 connector. Only problem is there’s not pin 70 on my harness. It’s just a dummy pin. I’ve also got No pin 17 on J1 for the high speed cooling fan control rely. What’s gonna be a my best option to work past this?
I really appreciate all of the help from you guys with this wiring process….definitely wouldn’t have made it this far on my own
 
#108 ·
R_shum said:
Sweet! I’ll get these eliminated and out of the way.

I’ve managed to make some more progress in the fuse box. Just need to run a few more ABS wires and a couple other misc wires. This leads into my questions …Pin 10 for X101. This is for the fuel level sensor that teminates into pin 70 on J1 connector. Only problem is there’s not pin 70 on my harness. It’s just a dummy pin. I’ve also got No pin 17 on J1 for the high speed cooling fan control rely. What’s gonna be a my best option to work past this?
I really appreciate all of the help from you guys with this wiring process….definitely wouldn’t have made it this far on my own
Click to expand...
the van uses a mechanical clutch fan driven off the water pump so you will need to add a wire here.
the van has a flat bottom gas tank and can get by with only one fuel level sensor, the CTS uses a saddle tank and takes an average of both tanks. You will need to add a wire here also. Your best bet is to cut a J1 pig tale off from your local junk yard, (same era as yours) cut it about a foot back. You will need to remove the inside cover then pry back the release tab and the wire will slide right out. Any color wire will work just keep track. You could find a video on you tube on how to do this, LT1swap.com explains how to do it also. If your lucky you might be able to rob one from your V6 harness but I think the Bosch wire/pins are different. Try to De-pin a couple of wires on the blower motor wires you removed and you’ll get the hang of it, it’s not that hard. Remember, your tuner will need to add these when he does your tune…
 
#109 ·
If anyone is curious how the CANBUS system works. all the modules are just daisy chained together and wired series/parallel. You can see in this drawing there are only 5 modules. the network starts in the ECM (notice the 120ohm resistor) the next module in the circuit is the BCM then the EBCM, fuel pump module and last the TCM. The last module will also have a 120ohm resistor to signal the end of the network. The DLC (where you plug in your scan tool) is just tapped in anywhere in the network. communication can travel in both directions and can also skip modules by the way it’s wired internally. The communication wires are twisted so not to receive any interference from other wires in the same loom.

Image
 
Discussion starter · #110 ·
Big_kid said:
If anyone is curious how the CANBUS system works. all the modules are just daisy chained together and wired series/parallel. You can see in this drawing there are only 5 modules. the network starts in the ECM (notice the 120ohm resistor) the next module in the circuit is the BCM then the EBCM, fuel pump module and last the TCM. The last module will also have a 120ohm resistor to signal the end of the network. The DLC (where you plug in your scan tool) is just tapped in anywhere in the network. communication can travel in both directions and can also skip modules by the way it’s wired internally. The communication wires are twisted so not to receive any interference from other wires in the same loom.

View attachment 625892
Click to expand...
I Was wondering why they were twisted…
 
Discussion starter · #111 ·
Big_kid said:
PIN 26 from the fuse box will go to PIN 11 on the TCM
this is the 12v signal from the fuse box to “wake up” the TCM module.
it’s a dark blue wire circuit number 5985
Click to expand...
There is a wire running from pin 18 on the ECM to PIN 11 on the TCM. Should I still go ahead and run PIN 38 from the fuse to pin 18 on the ECM and PIN26 on the fuse box to PIN 11 TCM ?
 
#115 ·
Big_kid said:
the van uses a mechanical clutch fan driven off the water pump so you will need to add a wire here.
the van has a flat bottom gas tank and can get by with only one fuel level sensor, the CTS uses a saddle tank and takes an average of both tanks. You will need to add a wire here also. Your best bet is to cut a J1 pig tale off from your local junk yard, (same era as yours) cut it about a foot back.
Click to expand...
instead of doing this you could just de-pin and move the wires used for the O2 sensors (after the cats) I’m guessing your not going to be using these seing you have headers. There will be six of these wires on J1. PIN # 10, 11, 49, 64, 65 and 69
 
#116 ·
AIR CONDITIONING CIRCUIT:
You should of saved the three wire harness for the high pressure A/C sensor (off the V6 harness). This sensor is on the condenser by the radiator.
the RED/BLACK wire will go to PIN 12 on J1 (ECM)
the TAN wire will go to PIN 13 on J1
the GRAY wire will go to PIN 34 on J1

you might need to add a wire (use one of the 6 wires from the O2 sensors) to PIN #63 on J1
this wire will go to PIN 5 on the fuse box
PIN # 33 from the fuse box will go to A/C compressor clutch
 
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