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Discussion Starter #1
I bought a 98 mustang GT with the 4r70w that has a code P0743 TCC solenoid electrical. its symptoms are it feels like it may be locking in second, if I shift into second on the shifter the car dies. if I start out in drive once it hits second the car jerks bad, like I was letting out a clutch on a manual without giving enough gas, Unless I get on the throttle hard, then it seems to avoid the jerkiness.. lol. Also at times it wants to stall when coming to a stop sometimes it does die. and another symptom is at highway speed it feels like its kicking in and out of lockup until i give it more throttle. any info would help. I did change the TCC solenoid and had a local tranny shop test drive and use their scanner, they said there was a bad shift solenoid, and I think something with the epc. but on a cheap autozone scanner the only code is the p0743. they want to rebuild the tranny at $1200, just looking to see if theres a cheaper fix, cause I dont really trust them.
 

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assuming the new tcc solenoid is good, then it could be as simple as the wiring being faulty. check all the wiring as well as the resistance of the solenoid. You can find the resistance values in the Tech Articles from the front page (not forum) in the Transmission section, Ford OD Transmissions 101.
 

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Discussion Starter #3
I checked the one I put in And also the one I to ok out and both were good, right about 13.5 ohms. I was trying to figure out how to check them at the tranny plug on the firewall to see if I get the same reading from there or if its different or nonexistent there. but I'm not sure which pins on the plug to use. and I cant seem to find them online.
 

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I checked the one I put in And also the one I to ok out and both were good, right about 13.5 ohms. I was trying to figure out how to check them at the tranny plug on the firewall to see if I get the same reading from there or if its different or nonexistent there. but I'm not sure which pins on the plug to use. and I cant seem to find them online.
you need to read the article I specified. The info is there.
 

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does the car have a tune on it? someone may have goofed up the tcc settings

if you go to the ecu connector you can unclip the tcc wire from the harness and see if the issues go away
 

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Discussion Starter #6
no tune as far as i know car is stock. i was under the dash and see some wires are spliced like they had a remote start or alarm, do either of those connect to a tcc wire at all?

decipha, you mean just cut the wire to try? i was thinking that but wasnt sure if it would work.

i just tested the TPS and when i spin the throttle the ohms dont change at all. i know tps cant mess up lock up... but i dunno about the p0743 code...
 

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Discussion Starter #7
and i did find the to pins to test tcc from harness and im only getting about 4 ohms.... but when i test right on the solenoid i get between 13.5ish.... if a wire was broke i wouldnt get any resistance? or does lower resistance make sence?
 

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Discussion Starter #9
TPS was bad.... but didnt help the jerky's or stalling. :( also clipped the brown/orange tcc wire... still stalls when i hit second. :confused:
 

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test the tcc by way of unplugging the main connector at the pcm and then probe the pins on the harness at the pcm harness connector inside the car [because this is THE resistance the pcm actually sees]. Then compare the resistance versus what is in the transmission article.

Don't clip any more wires. Repair anything you "clipped". You're not doing this correctly. The reason you saw 4 ohms is because you didn't disconnect the main connector at the PCM.

If you bothered to read the transmission article, [for the third time mentioned], it's all there.
 

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Discussion Starter #12
I DID read the article a few times, I just didnt figure there would be that much difference in resistance between checking it at the computer or at the plug under the hood considering they are about 3 feet apart and the PCM was not hooked to the plug I tested from. I will try it at the PCM Next, Now my other issue is I'm sure the ohms you are referring to for my car is the PWM specs, but those are for 95 and older which my car is a 98. and the older aode and 4r70W transmissions had a Solenoid the ranged from 1-3 ohms and the newer ones had a range from 10-15 ohms. now in the article it says the range for 95 and older should be 1.1 to 1.7 ohms when tested at PCM and the range for the solenoid itself is 1-3 ohms. should I read a full 10-15 ohms at PCM on mine or does the resistance change when your reading it through 6 feet of wire? like I said wiring is not my thing. sorry if you feel I'm ignorant for for measuring from the plug on the fire wall instead of at PCM. didnt think it would matter as long as measured from the tranny half of the harness with the PCM side disconnected
 

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Well when you dont say which pins you actually tested how can we know where you're testing them? We can't .

There shouldn't be any difference between the results at the bulkhead harness and at the pcm. But also realize there is no way ADDING wiring can decrease the resistance.

If you wanna go with your article that you found, great. I would trust the article written by the former Ford engineer who had a hand in developing the 4R70W.
 

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Discussion Starter #15
i said the tranny plug on firewall... didn't know it was called the bulkhead, my apologies. is there any way of contacting him to verify the change in tcc ohm. because it does say right in the article the pwm reading is for 95 and older. if it did change maybe it could be added? i dunno. cuz i did read that article a few time before even joining and asking a dumb question.
 
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