Hey there. I am running into an issue now when I swapped out the transmission that I originally had running in the car. It was a 2003+ 4t60e-HD and it was fine with my PCM computer 12209624. Now I have the older style 4t60e trans with the same wiring harness which is creating a problem with the computer and getting the gears right. I get the car to shift into 2nd and no further. How can I get past this without having to redo the wiring harness. I believe the difference that is messing up the pcm and eveything is what my friend told me, being the external gear selector. the 1997-2002 have the external and the 2003+ have internal? How can I fix this! I need it done so I can drive the project around town finally!
03 4T65E and up are controlled differently by the PCM then 97 to 02 but if you are actually using a 4T60E tranny then you need to rewire as a 96 SSEI and use the matching 96 PCM
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DARN Cars now open with Over 30 years wiring experience between cars and trade as an avionics technician in both Canadian Air Force and civilian aviation. Over 25 years experience building and modifying cars. Over 10 years of full Fiero engine swaps and harnesses building and still going.
Fieroflyer. Yes I believe that you are correct. I think I got my numbers screwed up. I had the setup out of my pontiac grand prix gtp and that should have been a built 4t65e-hd. So then if I have an older style 97-03 4t65e-hd but with a newer style wiring harness for a 2003 transmission then I wonder if I can swap out the pcm with an older one and burn a new setup to the pcm to make it work. Does that sound like it is on the right track for progress? Thanks for the help guys. I almost have the thing on the road and this little problem is being a headache.
Fieroflyer. Yes I believe that you are correct. I think I got my numbers screwed up. I had the setup out of my pontiac grand prix gtp and that should have been a built 4t65e-hd. So then if I have an older style 97-03 4t65e-hd but with a newer style wiring harness for a 2003 transmission then I wonder if I can swap out the pcm with an older one and burn a new setup to the pcm to make it work. Does that sound like it is on the right track for progress? Thanks for the help guys. I almost have the thing on the road and this little problem is being a headache.
If you can get ahold of a 98 PCM it should run without issue if not PM me and I'll swap out PCM's with you. However, I'm not sure if it is that easy as you may NEED the wiring to match. I don't build harnesses and I can't see all the differences in the wiring.
Hey, What do you guys think about this. the wiring harness was made by red devil river or Phonedawgz who by the way did awesome job, first turn of the key start! but the harness was made for an 06 style GTP 4t65e-HD trans which uses an internal gear selector. Red devil river made a type of hybrid or modified harness that used the external gear selector from the earlier cars for the input to the PCM/ECM. My harness has the wiring for the external gear selector which has two plug ins, one larger that my harness has and uses, no smaller plug yet. So, my friend Chris was saying that since this was the case, I am needing the smaller of the two plugs and that should and will fix the problem because the computer is looking for the output from the older style transmission gear selector and it is not there since the harness was made for the newer transmission. watcha think? I think that it makes sense and when I get back into town I am going to give it a shot. Anyone have an extra transmission gear selector plugs they could sell and send over? If not a run to the you pull it yard should yield good results.
here is the main larger plug to the gear selector, mind you I am missing the smaller plug to the front side of the gear selector.
I think you should ask phonedawgs...LOL as I am just guessing on what you need. Curious on how you installed the trans as it uses different brackets than the later years.
[This message has been edited by nosrac (edited 02-07-2015).]
Wiring wise the 03 has a few less wires from the PCM to the main tranny connector due to less solenoids in the tranny. To make this work with an 02 and older tranny and PCM these wires will have to be added, not sure if any others have to be moved or not will have to look at the diagrams
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DARN Cars now open with Over 30 years wiring experience between cars and trade as an avionics technician in both Canadian Air Force and civilian aviation. Over 25 years experience building and modifying cars. Over 10 years of full Fiero engine swaps and harnesses building and still going.
OK here goes the tranny plug will be missing pins N, P and R in the 03 that have to be added for the 02 and older. Tranny pin N a pink wire goes to PCM C1 blue connector pin 22, tranny pin P red wire to PCM C2 clear connector pin 17 and tranny pin R dark blue wire goes to PCM C2 pin 57. Other then that just use a 99 to 2002 PCM and you will be good to go
Alright so almost there. I have this for the wiring, which doesnt make sense. wiring of the tranny selector switch I think. I also have this website as a reference for making this all work. http://www.gmforum.com/4t65...transmission-297189/
Then I have the information, which you sent me, but the pigtail that I have for the transmission input is labeled a,b,c,d. I need info for which plug into the transmission for the n,p,r labels. and will it hurt to add in a ground for the fourth plug? or just leave that out. thanks a ton. I am almost there. just taken too long, ugh. Oh and it is crystal clear for what I have to do for adding in the pins for the C1 and C2 pins into the pcm plug. thanks for that.
The selector switch will already be wired in through the main electrical on the tranny they switched from external to internal around 02 or some thing like that. It is the main large round connector up on the side near the top of the tranny in 03 they removes the before mentioned wires from it. these are the wires you need to add back in from that tranny connector to the PCM
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DARN Cars now open with Over 30 years wiring experience between cars and trade as an avionics technician in both Canadian Air Force and civilian aviation. Over 25 years experience building and modifying cars. Over 10 years of full Fiero engine swaps and harnesses building and still going.
