Transmission Wiring

[Bull]

Has anyone here ever gone through the wiring connector for a 4L60E and found out what voltage each of the wires has, and when? I am wiring up a T56 in my car (doing conversion) and if I can grab power from the wires in that old harness down there, it would be convenient. Maybe I just have to test each one myself, but figured someone else might have already done it and that would save me the trouble.

This is the connector I am talking about (sorry for slight blur.)
http://img.photobucket.com/albums/v708/2ManyCars/DSCN3125.jpg

[Chris]

http://shbox.com/1/electronic_trans_controls.jpg

[Bull]

This site is already kicking LS1tech's ass.

Now, the only wire I see up there with voltage info is the one on the left. But, maybe I do not know how to read the diagram fully. Does it show how much power each wire gets, and in what position of the ignition switch (i.e. run, start?)

[hotrod96z28]

the one on the left says Hot in Run, Bulb Test and Start. i dont know about how much juice

[Chris]

Use the pink wire , it is the feed for all the soleniods. Battery power koer

[Bull]

Thanks for the additional info. What is "koer?"

Also, I need several types of wires, as I recall. The harness I am using is from tpi-parts on eBay. The directions tell me what power needs each circuit has. I can post those directions on here after I get home from work.

[hotrod96z28]

key on engine running

[Spartan7]

key on engine running

AKA 12v switched.

What year are you doing this on? OBD1 and OBD2 are different. OBD2 is much easier to wire up for the swap.

This is going off my 96. Take the 4L60E connector apart, and look in the back of the connector where all the wires run. You will see they all have letters assigned to them. Pin E should be pink. That is the 12v switched source you can use for reverse lockout and CAGS. There are 2 pink wires, make sure it's pin E.

I have all the swap wiring info for 96+ cars, let me know if you want it.

[Bull]

Spartan, thanks for the reply. This is on my '95 Formula, so OBDI.

Let me write here what the directions say about power needs, and maybe someone here will have done this on an OBDI car. Otherwise, I will have to muscle through it after doing some testing.

One general question I have is, if I cant find all the power I need from the wires in the automatic harness under the car, what is the best way to get ny wires back up into the passenger compartment to tap into the harnesses there? I mean, I have a hole in the trans tunnel for the T56, but I obviously don't just want to poke my wires up through that because it is unprofessional and the edges are sharp. Would I drill a small hole for some wires, put a rubber grommet in it, and then get up into the interior of the car that way?

I just want to do a pretty neat, non-hack job.

[Chris]

So you are going to run the additonal wires from the pcm? for the skip shift and reverse lockout? Seems pretty much a waste of time imho. Is that all you are trying to get power for down there?

[Spartan7]

For reverse lockout, you are going to have to tap a pin on the PCM, since no wire is there for OBD1 PCM's. For CAGS, I think as long as it's tuned out, you won't get a light. Mine would still throw a SES light with no resistor wired in (even with CAGS tuned out), so I had to wire up that harness. Can someone confirm this?

The only wires I ran through the shifter boot hole were for reverse lights. If you want a clean look, you are going to have to locate the 2 wires in the engine harness. It was just easier to wire it to the reverse light wires inside the console for me.

For VSS, you are going to have to get the new harness and splice it in. Your A4 harness won't fit in the T56 speed sensor.

Everything else is the same. If you want a stock-like install, you need to hook up: brake lights, reverse lights, clutch start switch, clutch pedal cruise control cancel, hatch release, VSS, reverse lockout, and CAGS.

Are you using this guide? http://www.afrashteh.com/tranny_pics/T56.htm
If you are, most of his wiring section is pretty good. Just don't wire up the hatch release like he says, it's wrong.

[Spartan7]

So you are going to run the additonal wires from the pcm? for the skip shift and reverse lockout? Seems pretty much a waste of time imho. Is that all you are trying to get power for down there?

It's not power you need, it's the command wires for the PCM to command ground to the solenoids, so they disengage. 12v switched is already there (I have no idea which wire, it's probably the same one as mine though). IMO, reverse lockout is in no way a waste of time.

[Chris]

It's not power you need, it's the command wires for the PCM to command ground to the solenoids, so they disengage. 12v switched is already there (I have no idea which wire, it's probably the same one as mine though). IMO, reverse lockout is in no way a waste of time.
I know what they are for. I didnt have either on my 6speed and I couldnt imagine hitting reverse. Idk how many of us race having to have to try and hit 5 gear as fast as possible.

[Spartan7]

I know what they are for. I didnt have either on my 6speed and I couldnt imagine hitting reverse. Idk how many of us race having to have to try and hit 5 gear as fast as possible.

:rolleyes: Maybe some of us don't want to have to strong-arm reverse all the time. If you don't mind it, then that's your business. But your sarcasm isn't really helping the OP here.

[Chris]

:rolleyes: Maybe some of us don't want to have to strong-arm reverse all the time. If you don't mind it, then that's your business. But your sarcasm isn't really helping the OP here.


I wasnt being sarcastic. And I thought thats just normally how the reverse was. I test drove a few cars stock that were like that.

[Bull]

To be more clear, here is the harness that I am using:
http://cgi.ebay.com/ebaymotors/T56-6-Spd-Transmission-Retrofit-Wiring-Harness-LT1-LS1_W0QQcmdZViewItemQQ_trksidZp3286Q2ec0Q2em14QQha shZitem563592f035QQitemZ370266009653QQptZMotorsQ5f CarQ5fTruckQ5fPartsQ5fAccessories

The harness does come with instructions about what kind of power each wire needs, but obviously it cannot tell me where to get that power from. And yes, I do want reverse lockout and even CAGS, since I am not reflashing the computer to eliminate CAGS. It's just a driver, so am I really going to be bothered by this?

Here is what the wiring instructions call for:

Reverse lockout gets "Hot in run" with a 10amp fuse added (inline, I am guessing).

CAGS: Gotta run a wire up to the PCM, apparently. Any suggestions as to the best routing for the wire? Any idea on which "pin?"

"Hot in run" with 20 amp fuse for backup lights

VSS:Yellow and purple wire in VSS circuit, wherever that is

[Bull]

When it talks about "pins" on the PCM, what does that even mean? Is the PCM that silver box to the upper-left of the pedals, under the dash? Looks like a real bitch to get my hands on to work on adding wires to it.

[Chris]

http://shbox.com/1/1995_pcm_conn_b.jpg



http://shbox.com/1/1995_pcm_conn_d.jpg

[Chris]

http://shbox.com/1/1995_pcm2.jpg

[Spartan7]

Wow, I didn't know they made a harness like that. That will make it more interesting.

Ok, getting to the PCM is not so bad. Re-pinning it might be.

For VSS, pull your A4 harness apart (pull the wires out of the sheathing). Follow the two wires for the current VSS connector back, then just splice into them.

For reverse lockout, you need two wires: 12v switched, which is already in the A4 harness, and the ground command wire from the PCM. This command wire is not pinned on the 95 PCM, so you have to do it yourself, and run the wire all the way to the reverse lockout solenoid. Same with CAGS.

The PCM is the grey box behind the passenger side wheel well. Unbolt it (2 bolts) and pull it out. You'll see 4 big connectors going into it. Pull off the red safety clips and unhook the connector you need. They are labeled by color on the PCM case. You need blue and black. Then find the pins. They should be labeled inside the connector, or on the back of it.

Reverse lockout: PCM blue connector, pin D6. Tap this, then wire this to pin "A" on the reverse lockout pigtail. Find 12v switched in the A4 harness (pink probably, use a multimeter). Wire that to "B".

CAGS: PCM black connector, pin B13. Wire to "A" on CAGS connector, wire 12v switched (you can use the same wire that you used for reverse lockout) to "B".

Reverse lights: That harness won't work with reverse lights. On A4 cars, the reverse light wires go from the fuse block to the shifter switch, straight to the reverse lights. On manual cars, they come out of the fuse block, through the firewall connector, down to the reverse lights switch, then back into the car and finally to the reverse lights. That's why it's just easier to wire it through the shifter boot. Otherwise you have to trace the wires all the way through the engine/body harness and through the firewall.

[Spartan7]

I wasnt being sarcastic. And I thought thats just normally how the reverse was. I test drove a few cars stock that were like that.

You mean they didn't have reverse lockout? Because with it unhooked, the solenoid will always be disengaged, meaning it will always be hard to get in reverse. There is no risk of hitting reverse while driving, as long as the solenoid is there. But then it becomes hard to get in reverse without it hooked up. The PCM engages the solenoid below 3 mph, allowing you easily into reverse. Anything above that and the solenoid disengages, preventing it.

[Bull]

Okee dokee, I am making some progress here. Hard to find time between work, house projects, and family. But, I've got everything wired except the VSS, reverse lockout, and CAGS. VSS will be a cinch, as I located the wires today, and it's a simple splice job.

First, let me just ask if this is indeed the PCM:
http://img.photobucket.com/albums/v708/2ManyCars/DSCN3136.jpg

Perhaps it will become clear to me once I remove it, but as of now, I do not fully understand what it means to "tap" the various necessary pins on the PCM for the reverse lockout and CAGS.

As for CAGS itself, I ordered that harness with it just because I did not know how to avoid using it. In other words, what do I need to have done to my car's computer (and is this the same as the PCM?) so that CAGS is gone? If I do eliminate CAGS, would I just leave the connector for it plugged into the trans and just not wired?

Finally, Spartan, your directions to me do not indicate any type of fuse being necessary for the reverse lockout or CAGS circuits. The directions with my harness say to use a 10amp fuse. Do I need to run an inline fuse holder for those circuits?

Thanks for the help, it really is appreciated.

[Spartan7]

Yea, that's the PCM. When you pull out the PCM connectors, you'll see that some of the cavities don't have wires going into them. The ones I posted above don't have wires in them currently, so you have to do it yourself.

http://www.bfranker.badz28.com/96SS/skipshift.htm

That should help you out a little. I think the best way for you is to find a wire off the PCM that previously went to the tranny connector, and pull it out of the connector, then move it to the pin you need. Then you can just use that and splice your new harness into it.

But like I said before for CAGS, I'm not sure how it is for OBD1. This is if you want to disable CAGS (I can't understand why you'd want to keep it). If you are getting your PCM flashed with an M6 program, then you might as well have them disable CAGS as well while they're doing it. Then you don't even need the resistor, just plug it in.

And no, I did not add any fuses. The hot wire I already mentioned in the A4 harness is already fused. Don't go completely off the instructions for that harness. It's for a retrofit, for vehicles that never came with a T56.

[Bull]

Ok, the weekend means having some free time to try and finish this...so close!

Spartan, I took the PCM out and opened up the "Blue" connector as described and shown in that link you posted. Here's the deal.

It occurs to me that I don't have to do ANYTHING to get rid of CAGS. The T56 has the connector, but I think I can just leave it plugged in but not connected to power. Since my car was an automatic, the PCM had NO wires in slots 13 and 15, which are the two I'd have to disconnect to kill CAGS. Correct me if I am wrong, but I think I can just forget about CAGS completely. I should have ordered my harness without it, but my car will never know it was supposed to be there in the first place thanks to the A4 computer.

Now, on to reverse lockout. You mentioned tapping pin D6 on the "Blue" connector and wiring this to the A on the lockout pigtail. Well, there is already a wire in the D6 position. It is brown. Looking at the chart that Chris posted here, on an A4 car that brown wire in D6 is for the "Transmission TCC PWM Solenoid" whatever that is, and would have B+ voltage. For an M6 car, the wire there would be light green, but the "voltage" boxes are left blank on Chris' chart. So the big question for me now is, can I just tap into that existing brown wire on D6 and run to terminal A on the reverse lockout pigtail? Or, because it is getting voltage from somewhere, do I need to disconnect it from where it is getting power from and then reroute it to the A terminal?

I hope that make sense. Once this wiring is done, I can button the interior back up and TEST the car after a LOOOONNNGG time being off the road.

[Spartan7]

It occurs to me that I don't have to do ANYTHING to get rid of CAGS. The T56 has the connector, but I think I can just leave it plugged in but not connected to power. Since my car was an automatic, the PCM had NO wires in slots 13 and 15, which are the two I'd have to disconnect to kill CAGS. Correct me if I am wrong, but I think I can just forget about CAGS completely. I should have ordered my harness without it, but my car will never know it was supposed to be there in the first place thanks to the A4 computer.

Doesn't matter if the wires are there or not, it's how the PCM will react. I looked it up, and here's the deal with OBD1 and CAGS. If you never hook it up, you will not get an SES light, but a code will be stored in the PCM. So no big deal really. But then again, I don't know if tuning it out will get rid of that. Call up the guys at PCM For Less, they'll know.


Now, on to reverse lockout. You mentioned tapping pin D6 on the "Blue" connector and wiring this to the A on the lockout pigtail. Well, there is already a wire in the D6 position. It is brown. Looking at the chart that Chris posted here, on an A4 car that brown wire in D6 is for the "Transmission TCC PWM Solenoid" whatever that is, and would have B+ voltage. For an M6 car, the wire there would be light green, but the "voltage" boxes are left blank on Chris' chart. So the big question for me now is, can I just tap into that existing brown wire on D6 and run to terminal A on the reverse lockout pigtail? Or, because it is getting voltage from somewhere, do I need to disconnect it from where it is getting power from and then reroute it to the A terminal?

You sure can. Just splice into that wire, since there's already one there and it's not being used anymore. Less work for you. Now that's the signal wire, so all you have to find is the 12v switched source in the original A4 harness and splice the other side of the connector into that, and you're golden.

[Bull]

Thanks for the reply, once again.

I ran the 12v switched pink wire (I tested it to make sure it was keyed power) from the A4 harness and ran it to one side of the reverse lockout solenoid. I then cut the brown wire exiting the PCM at the D6 slot about 6" away from the box. Since that wire was shown as having battery power in the diagram Chris posted, I figured it must be spliced into power somewhere in its path. Knowing that that I don't need any power to that wire, I just cut it at a point where I knew it was not getting juice from anywhere. I then spliced on another length of wire that I ran in a loom down to the other terminal of the lockout solenoid.

Now, I connected the battery, started the car, and shifted into reverse a few times. It definitely takes some effort to do, definitely more so than the other gears. Is this normal, with a properly wired lockout solenoid? I don;t see how I can test whether it is working...I'm certainly not going to see if I can hit reverse at speed! But, I thought it was supposed to be easy to hit reverse when parked, then impossible later? But maybe I am mistaken and even when parked it is harder to get into that gear than the forward gears?

[Spartan7]

No, reverse should be as easy as any other gear with the car sitting still and the engine running. Is the shifter hard to move over, or hard to move up? You can test the reverse lockout solenoid by taking it off the tranny and applying 12v to the pins, and see if the plunger moves. If so, it's good. If the solenoid is good, then it's your wiring. But it sounds like you wired it up right.

Just making sure, you do have an M6 program on your PCM right?

[Bull]

No M6 program, no. Just the stock A4 one until the swap is done and I can get a reflash somewhere. I called the dealer the other day and the service manager had no idea if they could reflash the PCM for me...said he'd get back to me and never did.:hmm:

Is the lockout solenoid the top-most one right below the driver's side lip of the shifter basin? I see connector there on the outside, and inside noticed a plunger of some kind sticking out into the shifter basin area.

Hopefully, it is easy to access because after all this work I don't want to disconnect parts to get to the damn solenoid to test it!

The shifter was difficult to get over to the right, as well as then up into the Reverse position. I did not have my foot on the brake pedal at the time...might that make a difference? I heard somewhere that it might.

I'm going to put the car down on the ground and test drive it in the next couple days, so hopefully it is ok to drive with the Reverse like this. I'm guessing it is, and that the only danger is when it is permanently bypassed.


No, reverse should be as easy as any other gear with the car sitting still and the engine running. Is the shifter hard to move over, or hard to move up? You can test the reverse lockout solenoid by taking it off the tranny and applying 12v to the pins, and see if the plunger moves. If so, it's good. If the solenoid is good, then it's your wiring. But it sounds like you wired it up right.

Just making sure, you do have an M6 program on your PCM right?

[Spartan7]

Is the lockout solenoid the top-most one right below the driver's side lip of the shifter basin? I see connector there on the outside, and inside noticed a plunger of some kind sticking out into the shifter basin area.

Yep, that's it. But it's not going to work if you don't have a M6 PCM. You can get it reprogrammed by either of these:

http://www.pcmforless.com/
http://www.madz28.com/

[Bull]

See, I'm a newb to this. I should have realized reverse lockout would not work prior to getting the M6 reflash, but I just didn't think about it.

Have you used either of the two companies listed? In your opinion, is it better to send your PCM to them to be done, or buy one outright to avoid the car being down and waiting?

[Spartan7]

I've used PCM For Less a couple times. They do good work. If your car is stock, you could just get a used one off the forums, but a tuner can dial in any combination you have. They can disable CAGS or VATS as well. Just take a look at their order page for all the options they have.

If you don't want to wait for yours to come back, they have a core charge, meaning they will send you one already tuned for extra, then you send yours to them when you get the new one, and they refund your money when they get it.

[Bull]

I communicated back and forth with Bryan Herter from PCM For Less today. It'll run me $175 to have the work done, which includes an M6 tune, lower fan temps, CAGS delete, 15-20hp increase, and slight economy increase.

I'd rather not drop $175 right now, so if you see someone selling an LT1 PCM, please let me know. I'm on the hunt.

As far as that goes, does it matter what year I get? Does it need to be the same year as my car i.e. '95?

[Chris]

You need to get one from either a 94-95 to work correctly with your wiring. Pcms generally run around 100-125 though you can always sell you factory one to offset the cost

[Bull]

Not that much of a savings then, really. But selling mine afterward does make sense.

And while I decide, I can still drive the car, right? I just won't have reverse lockout and the speedo will be way off, no other issues?

[Chris]

You may throw some codes for the speedo vs rpm being off but I wouldnt think there would be much of an issue. I bought my car with a swapped 6 speed and learned that it wasnt tuned and it was fine other than the speedo being off

[Bull]

The both of you have been very generous with your time and with responding to my many, many questions. Without your help, I would be in a much more difficult position.

[Chris]

Thats what we try to do =) Better bet would be to order yourself up a cable to tune your car and begin learning that. this way you can really dial it in. Alot of ppl over on Camaroz28.com I hear are pretty good with giving out files and what not for baselines

[Bull]

Thats what we try to do =) Better bet would be to order yourself up a cable to tune your car and begin learning that. this way you can really dial it in. Alot of ppl over on Camaroz28.com I hear are pretty good with giving out files and what not for baselines


What's the learning curve on that like? Because, aside from internet use, I am not adept at computer work. I need to start driving this car ASAP (currently borrowing father's '96 Impala SS to get to work) so if tuning on my own is going to be a big project this might not be the best time.

[Chris]

Ah , Then Id just say wait for the mail tune. I just got into tuning myself. Lots of cool stuff to learn but its time consuming to see all that you can do

[Bull]

Well guys, I got the car down off the jack stands and tested it out...everything seems to work great, as far as all the gears and the hydraulics! Woohoo! Just need to get that (expensive) reprogramming done and I'll be all set with the swap.

Thanks again for all the help. This one thread was way more helpful than the several I have started on ls1tech in recent months. I'm not even going to bother checking over there any more. :claps: