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4r70w Cel P0743

section525

sextion525
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City, State
Red Bluff, Ca
Year, Model & Trim Level
1975 Ford Bronco 4x4
This check engine light is killing me. I can't get the truck smogged. The smog check computer knows I just cleared the codes befoere I showed up because ALL the information is gone along with my P0743 code.

So, I am getting a P0743. Transmission Torque Converter Solenoid. Now, as far as I can tell the truck runs and shifts fine. Which sucks. :p

Is the TCC accessable by removing the pan? What am I getting myself into here? The guy at the smog place gave me a 7 page print out for a self diagnostic.. but it appears to be in a different language! :p I have a spare tranny I can swap parts off of if the fix is easy.
 



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I hate CA emissions nazi's, geesh.

In CO they will no longer fail you due to a MIL, because the MIL can be illuminated for reasons other then just emissions related sensors (perfect example here)

I would sure like to know why a trans shift solenoid code fails you at tail pipe emissions?

is this the ONLY code you get?
I would check the wiring plugs at the trans, Mine was ever so slightly not pressed in 100% and caused me all sorts of grief.

check the big square plug on the side of the trans.
Check the white plug on the pass side of the trans (hard as crap to get at because of the cat converter and heat shield being there. I ended up accessing mine through the floor access plate)

My Actron software says: P0743 = Torque Converter Circuit Electrical. This to me means the PCM is not getting a signal from the trans = check wiring first!
 






Yeah, this is the only code I have. It's lame.

I've pulled the large harness off the tranny, cleaned it, and re-connected. I'll try the white one. I hope it's that easy. Otherwise it's going to sit with expired tags until I get home from Mexico. :rolleyes:
 






Pulled the white harness... full of tranny fluid. WTF? That's not normal.
 






wierd.

Drop the pan?
 






The P0743 means the computer failed to detect an voltage drop across the TCC solenoid... so it is either shorted, or open. shorted is unlikely as huge driveability concerns pop up (like stalling the engine when you come to a stop) so your is undoubtedly "open" and you do not have TCC lockup.... it is either the solenoid or a problem in one of your harnesses. I can lend you a spare TCC solenoid to substitute and let you borrow the transmission tester if you like. That solenoid is a modulated one....btw.

You can measure resistance at the plug.... the green wire (far right 2nd row - where top is 2 pins, middle is 4 pins and bottom is 3 pins) is TCC power and the bottom row far right is the TCC ground return. (green/white stripe). You should show 10-16 ohms.
 






Are hard is the solenoid to get to? I opened up my other '99 tranny to see what I was getting into. Apparently, it wasn't 100% drained! :confused:
 

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The TCC is the single black solenoid. It has an ear tab on the 96 and a soft wire connector. We can swap the rebuilder 4R70W and the 4405 on the way down to mexico and you can pick up the replacement solenoid and the tester on your way back if you like. Least I can do!
 






they are never 100% drained hahaha
 












Glacier991 said:
The TCC is the single black solenoid. It has an ear tab on the 96 and a soft wire connector. We can swap the rebuilder 4R70W and the 4405 on the way down to mexico and you can pick up the replacement solenoid and the tester on your way back if you like. Least I can do!

I think I'll be leaving on Saturday. You'll be around? If anything I can just leave it on your porch or something.

Also, will the replacement solenoid work on a '99? The one in my truck and my other spare are both 99s. The rebuilder you're getting is my old '96 one. Which still works awesome BTW! :cool: :p
 






I am curious to know but if my information is correct the only difference between uyour 99 and 96 trans will be:

the wiring order inside the plug
and
the 98+ uses a digital trans range sensor, whereas the 96-97 is actually analog even though its called a DTRS.
 






They changed over to a different hard connector in lieu of an internal wiring harness in 98. So for a 96 you need the earlier style TCC solenoid. I believe I have both. Which one do you need? ( I am practically a 4R70W parts house here).

Depending on time I can meet you enroute to save you some time on Sat... like Sac Metro airport etc....
 






Yeah, the hard connector is what I remember being different.

I need the newer style. I don't have anything 1996 in my drivetrain anymore.
 






section525 said:
I need the newer style. I don't have anything 1996 in my drivetrain anymore.


(cueing up the theme song to the old TV series "The Jeffersons")

"Movin on Up!!!"

And that trannie pan drop looks like you were slaughtering Hogs.... geeze... at least it's RED fluid.... let me double check but I am pretty sure I have a 99 TCC...I recommend you take the tester too.
 






Okay. If not couldn't I just pull the one off my other '99 tranny? What exactly does the tester do? Just makes sure everything in the tranny is dope?

As far as meeting you.. it will be the begining of a 32 hour road trip. So an extra few miles/minutes wouldn't make a dent. But the airport would be cool. :D
 






the PCM determines which DTRS you use not the rest of the drivetrain.

I am guessing your garage looks something like mine these days, parts parts and more parts
 






410Fortune said:
the PCM determines which DTRS you use not the rest of the drivetrain.

I am guessing your garage looks something like mine these days, parts parts and more parts

It's getting better. I'm down to two transmissions, one transfer case, one motor, some torsion bars, spare headers :p , three front driveshafts, some shocks, a factory sub, hatch parts, and probably some other little stuff.

I'm dropping most of it off at Glacier's! :D
 






That reminds me. Wasn't your motor in my garage for a few months??
 



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Pfffft I put it all in my crawlspace or my dad's barn. I dont get rid of parts, NEVER! hahaha

I have WAY too much crap, but nothing compared to some of my pack rat friends! hahaha if you keep it orgaized at least it doesnt look like a junk yard!

You can never have enough transmissions :)
 






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