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Hello all, I hope I'm posting this question in the right place. (new member). I have a 95 Taurus Wagon with the 3.0 AXOD. I've had pump problems so I replace the valve body with a re-built complete with all new solinoids and EPC solinoid. Most of the problems went away except one and it's driving me crazy. About every 30 miles the tranny will lock into "high pressure" causing very harsh engagement from park to drive or neutral to drive. Reverse is fine and smooth. I would disconnect the battery for about 10 minutes to reset the PCM and the problem would go away for about another 15 to 30 miles. I replaced the PCM with a known good one and another 30 to 35 miles later the same problem happened. Could it be the VSS "burping" that would cause this to lock into the fail safe mode (high pressure) in the PCM ?. Again, resetting the PCM temporally clears this problem. Tranny shop claims it's mechanical and wants to replace the trans. I still think it's electrical. Anyone else been through a similar problem ?. I have a factory shop manual but no Rotunda tranny tester. Thanks in advance for any input.
 

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I've seen defective VSS hiccup, but never burp.

I don't think the problem that you are describing could be caused by a defective VSS, but a new VSS is cheap. Little more than $20 from Kragen/Parts America or NAPA for house branded box with a Ford trademarked part inside.

I would suspect the PCM is defective myself.
 

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I've seen defective VSS hiccup, but never burp.

I don't think the problem that you are describing could be caused by a defective VSS, but a new VSS is cheap. Little more than $20 from Kragen/Parts America or NAPA for house branded box with a Ford trademarked part inside.

I would suspect the PCM is defective myself.


Thanks for the reply. PCM is good. Removed from my other Taurus and works fine in that car. Matter of fact the PCM from my Wagon works fine in my other 95. Ruled out the PCM. One thing I've learned about PCM's and sensors is Garbage in/Garbage out.
Just curious if anyone else had this problem.
 

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Hello all, I hope I'm posting this question in the right place. (new member). I have a 95 Taurus Wagon with the 3.0 AXOD. I've had pump problems so I replace the valve body with a re-built complete with all new solinoids and EPC solinoid. Most of the problems went away except one and it's driving me crazy. About every 30 miles the tranny will lock into "high pressure" causing very harsh engagement from park to drive or neutral to drive. Reverse is fine and smooth. I would disconnect the battery for about 10 minutes to reset the PCM and the problem would go away for about another 15 to 30 miles. I replaced the PCM with a known good one and another 30 to 35 miles later the same problem happened. Could it be the VSS "burping" that would cause this to lock into the fail safe mode (high pressure) in the PCM ?. Again, resetting the PCM temporally clears this problem. Tranny shop claims it's mechanical and wants to replace the trans. I still think it's electrical. Anyone else been through a similar problem ?. I have a factory shop manual but no Rotunda tranny tester. Thanks in advance for any input.

First of all I apologize for up a topic so old, but it is important that I do so I share my problem and so maybe someone can help. I searched exhaustively someone with similar problem and only in this post found.

My problem is exactly the same as "lindy26", exactly! If I reset the PCM then it works fine for a certain 15 miles shortly after this period the PCM commands the EPC so that the pressure becomes extremely high causing "punch" whenever you move from P to D or N to D, the gear changes are still good, just a slight firmness in the changes.

This transmission was totally reconstructed, with the transgo kit installed, PCM was changed to test and has problem continue, VSS (genuine) is new, clean and tested MAF, TPS tested, MLS is new.

Anyway, a very intriguing flaw, if you have had this problem or imagine a solution leave a comment.

The car is a Taurus 1995, 3.0 Vulcan with AX4S

Thank you.
 

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Welcome to TCCA.

You might try going here & log in, BBB Industries- Premium Alternators, Starters, Power Steering Products and Turbochargers | TSB's & Wiring Diagrams, then open the 95 Taurus Engine & Tranny wiring pictorial files & take note of the boxed descriptive notes of the different sensors that can affect the EPC operation & then scan for pending, or set trouble code clues for any of those sensors, or try monitoring those sensors for questionable output that would have the tranny controller corrupt the engine, or EPC operation.
Some thoughts for consideration, let us know what you find.
 
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