# What's a "Shift Solenoid A malfunction"?



## watcher (Sep 4, 2006)

I have an 02 Ford Focus that suddenly stopped shifting into overdrive. I took it to a parts store and pulled the fault code "P0750 Shift Solenoid A malfunction". That tells me a whole lot of nothing. Anyone here know what that means and what might be the problem?


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## agmantoo (May 23, 2003)

As you are aware, the transmission stopped shifting into overdrive. In failing to shift the vehicle will use more gas and pollute more. The computer system is telling you that solenoid A has malfunctioned. Solenoid A is the device that shifts the transmission into overdrive. The OBD II tester is giving the fault code "P0750 Shift Solenoid A Malfunction" indicating the coil in the solenoid or its associated circuit is either shorted or open.


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## Beeman (Dec 29, 2002)

Yea, what Agmantoo said. The trans physically shifts when the computer completes the circuit for the required solenoid. It usually has 3 solenoids, 2 for shifting and 1 for torque converter clutch apply. your results may vary as I have never physically worked on that particular trans. The switching of application of the 2 solenoids gives you the gears. Both solenoids are usually the same part # so you would need a manual to identify it. it would also be wise to diagnose whether it's the solenoid before replacement. Usually using an OHM meter and measuring resistance at the connector will give you the answer. Solenoids also clog or stick sometimes and in that case resistance would be correct yet the solenoid couldn't physically activate.


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## watcher (Sep 4, 2006)

Beeman said:


> Yea, what Agmantoo said. The trans physically shifts when the computer completes the circuit for the required solenoid. It usually has 3 solenoids, 2 for shifting and 1 for torque converter clutch apply. your results may vary as I have never physically worked on that particular trans. The switching of application of the 2 solenoids gives you the gears. Both solenoids are usually the same part # so you would need a manual to identify it. it would also be wise to diagnose whether it's the solenoid before replacement. Usually using an OHM meter and measuring resistance at the connector will give you the answer. Solenoids also clog or stick sometimes and in that case resistance would be correct yet the solenoid couldn't physically activate.


This a DIY fix or should I bite the bullet and pay a trans shop?


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## agmantoo (May 23, 2003)

Using a good ohm meter and taking a reading at the connector would isolate whether the coil in the solenoid is shorted or open or reading correctly. If the reading is the correct ohms then the problem could be as Beeman stated as the solenoid being stuck or it could be that there is a bad connection from the computer to the solenoid. Determining which of these is at fault could avoid a lot of work and expense. 
How many miles are on this vehicle and how much service/preventive maintenance has been performed on the transmission?


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## Beeman (Dec 29, 2002)

watcher said:


> This a DIY fix or should I bite the bullet and pay a trans shop?


 There's always variables to ever problem, in this case it's the Y. I was never a trans shop but I repaired many with similar problems. To DIY it will require at the very leat a digital VOM and a factory manual or equivalent, not a cheapo manual from the parts superstore. Much depends on the Y as in your ability, patience and what time and aggravation is worth to you.


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## watcher (Sep 4, 2006)

Car's had 157,000 miles and was bought used. I changed the filter yesterday and the fluid looked like thin used motor oil than trans fluid. I have an digi ohm meter but the only manual I have is a crappy Hanes. Its usually 'good enough' because I just need to know any little tricks needed for what ever vehicle I'm working on. 

After the fluid change I did a short test drive (it was almost dark) and then/now it no longer tried to shift into OD which used to cause the rpms to jump as if the trans was out of gear. It just stayed in 3rd. I have spent this morning working on a little gasket that was leaking coolant so I haven't done any more with the trans. Taking a break now.


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## agmantoo (May 23, 2003)

When you had the pan off the tranny were you able to see the small solenoids and the wires going to them?


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## cfabe (Feb 27, 2005)

Was it doing this before or did it just start after you changed the fluid/filter? Double check the fluid level first of all. You might consider pulling the pan and making sure you didn't break/pinch a wire and that you have the filter installed correctly. 

There is some problem with the shift solenoids in the focus transmissions though. I don't know the details but my brother has one and just has his repaired for about $800. I think it involved removing the valve body to rebuild it or repair it. It was expensive but less than a complete transmission rebuild. His was doing the same thing, not shifting into overdrive.


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## watcher (Sep 4, 2006)

cfabe said:


> Was it doing this before or did it just start after you changed the fluid/filter? Double check the fluid level first of all. You might consider pulling the pan and making sure you didn't break/pinch a wire and that you have the filter installed correctly.
> 
> There is some problem with the shift solenoids in the focus transmissions though. I don't know the details but my brother has one and just has his repaired for about $800. I think it involved removing the valve body to rebuild it or repair it. It was expensive but less than a complete transmission rebuild. His was doing the same thing, not shifting into overdrive.


It started before the filter change. I had read sometimes changing the filter could resolve the problem.


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## watcher (Sep 4, 2006)

agmantoo said:


> When you had the pan off the tranny were you able to see the small solenoids and the wires going to them?


Saw them. 

Could the computer still think there is a problem because the fault code hasn't been cleared? I can hope can't I?


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## Beeman (Dec 29, 2002)

When you had the pan off you might have been able to remove each solenoid and look at the end of it. they generally have a small screen that sometimes gets plugged with worn clutch debris or the little pintle valve itself gets stuck. You also could have OHMed them and possibly figured if you had a bad one. They operate on 12V and you possibly could have just activated them with jumper wires to see if they worked.


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