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Originally posted by lgy:
The rpm doesn't increase at all. What's that mean? Sounds this is a clue to my problem.
That means that your TCC did not disengauge. See, what happens in this test - is once your engine is at operating temps, your TC will begin to function. So, as you are cruzing down the highway at 50 mph, your TC should be locked. When you apply the brake, this should signal the ECM to disengage the TCC solenoid, which in turn unlocks the TC. After a few seconds, after you release the brake, the ECM will tell then signal the TCC solenoid to lock the TC again.
Yours never disengauged, so that means that it was never locked to begin with. In this case, if it was, it would locked all the time. We know that is not the case, not just because of the code that you have, but because your car would not start if it was locked at start up.
As for the TSS, if you read that article in the link above, you will notice that the car in question started having all it's problems after a rebuild and when it would go up this step incline. Going up a step incline would cause the TC to unlock and the problem comes into play because the TSS cannot see the speed correctly, hince not locking the TC back. Once this code would set, the ECM would see this as a faliure and cause the system to go into "limp mode" or "fail safe mode". This is actually what is causing the rough shifting... in the case of the story anyway.
Phillip Jackson
`98 Mystique LS
262K+ and counting...
ATX rebuilt @ 151K
"This storm has broken me, my only friend!" RIP Dime
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Reading Unisys post reminds me....have you checked your grounding wires on the tranmission and brakes? Having a bad ground connection could be causing you problems.
An ounce of prevention provides a pound of cure!
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How to check the ground of them? I also have the ABS light on after I put everything back. I do remember there is a transmission grounding wire. But it is too tight on the transmission end and I just disconnect another end, but when I get everything back, I forget where this grounding wire connect to. I connect it to the battery ground. Does this cause the problem?
97 LX V6 2.5L
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Your ground strap needs to be grounded to the chassis as it was originally. I'd look at mine at tell you where it leads to but I have my motor out. Maybe someone else can tell you where the grounding strap on the trans mounts to. I do know that the brake lights are on the same grounding circuit.
An ounce of prevention provides a pound of cure!
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I remember I reversely connected the battery once when I use a booster cable to test the car before I put back the battery. Does that destroy some sensors?
97 LX V6 2.5L
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Reversing polarity can cause problems....to say the least....
An ounce of prevention provides a pound of cure!
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Finally get the Alex OBD-II scanner. After taking a road test, I found that the TCC is lock-up between 40-50MPH, but it becomes unlock beyond 50MPH. I thought this may cause the P0741 code. But, I really couldn't understand why this happened. How come the TCC becoms unlock beyond 50MPH?
By the way, I couldn't get the ranger sensor output no matter where I put the selector. If the ranger sensor is gone, why the tranny shifts perfectly in local driving and TCC also locks between 40-50MPH. I am really confused now.
97 LX V6 2.5L
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Hard-core CEG'er
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Originally posted by lgy:
Finally get the Alex OBD-II scanner. After taking a road test, I found that the TCC is lock-up between 40-50MPH, but it becomes unlock beyond 50MPH. I thought this may cause the P0741 code. But, I really couldn't understand why this happened. How come the TCC becoms unlock beyond 50MPH?
To try an answer this first part... I can only think of a few reasons off the top of my head right now.
1) ECM detects that the TCC, inside the TC, is slipping and disengages the clutch to keep it from overheating and possibly locking up solid.
2) Weak solenoid on the solenoid block.
3) Leaking Torque Convertor Clutch circuit in the valve body
If I were to take a guess between the two, I would have to go with #1 which could be caused by #3. This could be resolved by replaceing the TC. That is unless you also have a leak in the TCC circuit of the valve body, which is very common so you might as well replace the TC and Valve body at the sametime. There have been people here that have done it themselves for around $500.
Last edited by unisys12; 04/22/04 03:00 AM.
Phillip Jackson
`98 Mystique LS
262K+ and counting...
ATX rebuilt @ 151K
"This storm has broken me, my only friend!" RIP Dime
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Joined: Jan 2003
Posts: 34
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If I were to take a guess between the two, I would have to go with #1 which could be caused by #3. This could be resolved by replaceing the TC. That is unless you also have a leak in the TCC circuit of the valve body, which is very common so you might as well replace the TC and Valve body at the sametime. There have been people here that have done it themselves for around $500.
The truth is that I already have repalced the VB, TC and solenoid. At the beginning, TCC started to slip beyond 80MPH or climbing grade, if I drive below than that, it works fine. I first replaced the VB, no any improvement. Then I replaced the TC, problem becomes worse, TCC start slipping beyond 50MPH. Then I replaced the solenoid. No any help.
Now I am thinking probably it is the oil pump because the line presuure is in the low side. My next project is to replace the pump. I really don't have the confidence to rebuild the tranny. If the pump cannot cure it, I will quit forever. I really hate CD4E now. Why Ford design such a trash? The stupid engineers even design a filter inside tranny.
97 LX V6 2.5L
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If you don't feel comfortable rebuilding your own trans, I'd recommend you purchase rebuild unit from phoenix transmissions. You can get a rebuild for 800 dollars plus 100 or so for shipping.......
An ounce of prevention provides a pound of cure!
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