P0743 code and pass through fitting availability

TJBart

TJBart

New Member
Joined
Jan 6, 2021
Messages
8
Location
Tennessee
Hi - a few weeks ago I purchased a 1999 Jeep TJ with the 4L motor and 32RH 3 speed auto transmission. It had an error code P0743 when i bought it and I am now getting around to fixing it. Researching the code it says it is related to the torque converter clutch solenoid. The car shifts fine around town but doesn't appear to be locking the torque converter at highway speed (gas mileage is impacted).

I bought a new solenoid and installed it last night along with a new transmission filter and new ATF 4 fluid. I cleared the code before driving it, and the code came back as soon as I got on the interstate and got up to speed. Since the code came back I am now thinking it is a wiring or connector issue? I did notice that the fitting that passes through the transmission case that the solenoid plugs into inside the transmission was cracked and missing one side of the plastic connector. The 2 pins were still in place and the connector from the solenoid seemed to fit securely.

I've researched the fitting on this forum and I think it is part number 56038235, but when I search that part online it looks slightly different than the one on my jeep.

My part looks like this (not actually my part but found this on the forum - mine is broken on the opposite end)
Pic-03.jpg


When I search the part number 56038235 I see this

s-l1600 (64).jpg


The end outside the transmission looks like it will work, but the end inside the transmission has a different style connector than my solenoid uses. Wondering if anyone has any idea where to buy the fitting that looks like mine? If it is no longer available I am considering buying the solenoid and fitting shown above and seeing if the solenoid will fit my valve body. The other option would be to splice the wire ends off of the solenoid shown above onto my new solenoid so it would fit the connector. If anyone has had any luck retrofitting parts to replace this fitting I would love to hear about it.

Also, is driving the jeep with this code likely to cause any damage to the transmission, or other issues besides low gas mileage.

Thanks!
 
A little more info, NAPA has part number 56038235 and the photo matches the one I posted above (not the one from my Jeep). Their web site says it is for the 30RH transmission, which is the one that came in the 4 cylinder wrangler. Mine is the 6 cylinder 4L motor with the 32RH transmission so I am wondering if this part is interchangeable? Their part comes with the solenoid and the pass through fitting, so I could swap them both out if they will work. If anyone has tried this please let me know, as I hate to drop $90 and find out it doesn't fit.
 
So in case anyone runs into this issue, the part number 56038235, which is listed for the 30RH transmission also works on the 32RH transmission. It comes with the pass through fitting and the solenoid with the correct type of wire connectors. I installed it and my P0743 code seems to have cleared up.
 
  • Like
Reactions: Daryl, Modoc Guy, Blondie70 and 2 others
Nice post! I have the same code on my jeep, have been too lazy (and broke) to deal with it atm sadly. When I go about getting it fixed I will be sure to give this post another read.
 
It won't harm the 32RH when the lockup doesn't work, it just means slightly reduced cruising mpg and the transmission will run a little warmer. Nice job getting it fixed and working! 💪
 
So my CEL is back with a P0743 again, so I am thinking it might not have been the solenoid or pass through fitting after all. It is an intermittent issue, and clearing the code keeps the light off for a while before it comes back. I was thinking it could be a wiring problem outside the transmission, and I did find an old splice on at the PCM plug on the orange/green wire, which goes to the solenoid plug (see pic). I am suspecting there is a problem with the splice that could be causing an intermittent CEL, and would like to rework this connection. I don't think there is enough wire to re-splice it, so I was wondering if anyone knows if you can replace an individual female socket on the PCM plug, so I can add more wire?

Thanks!

IMG_0689.jpg
 
For plugs like the ones in our Jeeps there’s a tool to release the contact and wire from the plastic plug body.

I don’t know the part number, but I believe it’s called out in the factory service manual.

Check out the repair section of the forum and download a copy for your year. I think it’s in the front of the electrical section.

With the tool, you can disassemble the plug, solder a new wire to the pin and reassemble the plug.

I’ve seen websites selling OEM pin and socket ends for various auto manufacturers plugs, you could try looking for them if your soldering skills are weak.

It’s a tedious process to go through, but it can be done.

Also, while you’re doing that, I’d check and clean all your connections for the PCM since yours are missing the covers, and they’re probably fairly dirty.
 
  • Like
Reactions: Daryl
So I found the tool on Ebay (MILLER TOOL 6934 TERMINAL REMOVER) and it worked great to remove the socket from the plug and allowed me to rework the questionable splice. I also cleaned the plug with spray cleaner for electronics. Unfortunately my CEL came right back when I got up to highway speed. I am seeing 12V at the PCM terminal (orange/green wire) with the key on, so I think that means the wires are good between the PCM and the solenoid? I have replaced the solenoid so I am starting to run out of ideas. This is an intermittent problem and sometimes it can go for a day or more without coming back after I clear the code.

I am wondering if this could be an issue with the PCM? My limited understanding of this system is that the PCM tells the solenoid to fire by completing the ground side of the circuit when the computer decides conditions for torque converter lockup have been met (based on vehicle speed I guess?). Does anyone know a way to test the PCM to see if it is working properly? Could this be a ground issue on the PCM?

Thanks for any advice.
 
If it’s a computer issue, maybe the guy from Wranglerfix might have an idea.

I know there’s a way that you can notify him in a thread, but I don’t know how to do that.
 
I think I finally have this issue fixed. I had to replace the entire wire from the PCM plug to the transmission including the plug on the transmission end (used the plug off the old solenoid). I was able to re-use the pin on the PCM end and splice the new wire onto it. Two long trips with the new wire in place and no more P0743 (fingers crossed).
 
TJBart said:
I think I finally have this issue fixed. I had to replace the entire wire from the PCM plug to the transmission including the plug on the transmission end (used the plug off the old solenoid). I was able to re-use the pin on the PCM end and splice the new wire onto it. Two long trips with the new wire in place and no more P0743 (fingers crossed).
Click to expand...
That’s great! Kinda suspected you might have to do that.
It might have had a worn spot somewhere and was shorting out.

You may want to check the harness from your PCM down to the transmission to see if there’s any spots that have rubbed off insulation.
 
I too have been getting the P0743 on my 01' TJ. Even if I don't even get up to speed, when the TC should lock up.
Jeep would start bucking, when I came to a stop.

For what it's worth, removing the #11 fuse, will get you going, but your A/C wont work. I needed to get to work, myself...
You can also dissconnect the plug on the trans, just to get by, and replace the fuse, so your A/C works now.
But your CEL will remain lit.
I was due for PA inspection in a month, and didn't have the time to try replacing the TCC solenoid.
Somewhere I read, connecting a 30 ohm 10 watt resistor, into the plug that connects to the trans, will fool the PCM into thinking the solenoid is connected and working. I found a 30 ohm 7 watt resistor in my parts box. (I used to repair electronics).
Low and behold, it WORKED. After clearing the code from the PCM. I had no issues. And was able to get it to pass emissons inspection.
Granted, this is just a work-around. Until I have the time to replace the solenoid. Besides the weather was too cold to be working on it outside.
This might not work on later models, but it works on my 01'. I simply shoved the wires from the resistor, into the plug, and used a wire-tie and some electrical tape, to keep it from grounding out on the frame. Shoved it up into a channel in the floor. It's been fine ever since.
My TJ, never got more then 11.5 MPG since I bought it. But it does have over 200K on the engine, so it's really tired.
Hope this helps someone anyway...
 
That's a clever fix (even if you did necro a 2 year old thread). I've often wondered if fixes like this could be applied to other codes as a short term fix to get the CEL off to allow you to pass inspection. This is a thing in TX, unless your jeep is a 97 or 98 (as of 2023).
 
That's exactly my reason for using the resistor. To keep the CEL off, so it will pass emissions.
Got it to pass the last 2 years now. Only once in a while, I still get the code.
Then I just clear the codes, drive it for 2 days, to fulfill the "drive-cycle" and take it for inspection.
 
Top Bottom
Back