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Discussion Starter #1
Hi folks,

I have a few questions, hoping to get some answers.

My car will drive fine in first and second and third gears up to a certain rpm or speed and then starts to rev and doesn't move. Then I have to turn it off in order to get it to move again, then same thing. I plugged in the code reader and got P0752 Shift Solenoid Ckt A Stuck On and P0747 Pressure Solenoid Ckt A Stuck On. So, I'm going to check them, but trying to do as little work as possible to avoid changing anything unnecessary.

I always change the tranny fluid every 10K miles, but this time didn't do it yet at 15K miles. Service manual says change every 30K miles, so I'm ahead of the game. Car has 280K miles. runs great.

Question 1. Could one solenoid not functioning correctly be causing the other to throw a code? in order words if the Pressure solenoid A is bad, will it be causing the Shift Solenoid A to be stuck on? I don't know if the Shift Solenoid A and the Pressure Solenoid A correlate to each other? So, i'm not sure which one to pull off and check first? Which one should I check first?

Question 2. How do you check them? do you just apply 12 volts and see if they click? how many ohms to check for? a friend said testing them off the vehicle is different because they're not under pressure?

Question 3. I noticed when checking the tranny fluid, that it was quite high, about 2 times past the top mark. I know I overfilled it, but don't think I did it that much, so it seems higher than I last saw it and that was checking it while cold, and some guy was saying something about it possibly being a torque converter issue seal leaking? On and off when starting it first time of the day, it makes this fluttering noise (like shuffling cards), but goes away after starting and restarting it or after driving it for a mile, and it doesn't always make the noise. Any idea?

Question 4. When the tow truck driver rolled my car back when picking me up, he walked away and the car started rolling forward, so I put it in park. Then the guy hooks it up and starts pulling it forward onto the bed while it's in park and it made a click noise a couple of times before he noticed it. Could that hurt anything? It seems to be holding in park ok at this point.

Any help is appreciated. Please respond with question number. Thanks!
 

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Re Qs 1 and 2 according to the factory service manual, both codes are related and point to solenoid A stuck on because it failed or there is debris. It would seem important to know if the problem started after the tow in park or was it happening before.

Both codes go to testing solenoid A. To test it, check pins 1 & 2 with an ohm meter. Should be 3-10 Ohms.

Also, while looking at the pins so they are left and right, with the connector fins up and solenoid below, pin 1 is left, pin 2 right. Put 12V positive on pin 1, when pin 2 is grounded, the solenoid should click.

Should note, the manual states to confirm correct fluid level before starting diagnosis. Typically a bad idea to overfill the trans which can result in foaming (air pockets that don’t allow lubrication and cooling) and/or high pressure.

Don’t have an answer for Q3 on the torque converter.

Also don’t have an answer for Q4 as I don’t know if this trans has a parking paw and how it works in park. Sounds like you got lucky but also the reason why I brought up the chrono order when the solenoid problem started.

Hopefully the solenoid test will tell you and it’s only that. If you have to take it off, check it for debris.

Good luck!
 

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Discussion Starter #3
Re Qs 1 and 2 according to the factory service manual, both codes are related and point to solenoid A stuck on because it failed or there is debris. It would seem important to know if the problem started after the tow in park or was it happening before.

Both codes go to testing solenoid A. To test it, check pins 1 & 2 with an ohm meter. Should be 3-10 Ohms.

Also, while looking at the pins so they are left and right, with the connector fins up and solenoid below, pin 1 is left, pin 2 right. Put 12V positive on pin 1, when pin 2 is grounded, the solenoid should click.

Should note, the manual states to confirm correct fluid level before starting diagnosis. Typically a bad idea to overfill the trans which can result in foaming (air pockets that don’t allow lubrication and cooling) and/or high pressure.

Don’t have an answer for Q3 on the torque converter.

Also don’t have an answer for Q4 as I don’t know if this trans has a parking paw and how it works in park. Sounds like you got lucky but also the reason why I brought up the chrono order when the solenoid problem started.

Hopefully the solenoid test will tell you and it’s only that. If you have to take it off, check it for debris.

Good luck!
Hi, thanks for the testing info.
To answer your question...the problem started before getting towed...its actually the reason for getting towed.

Also, do you know which solenoids are which, which one is pressure solenoid A and which is shift solenoid A?
I have a diagram, but it doesn't say which ones are A. I'll try to attach it here.

113275
 

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In the diagram, upper one is A. Lower one is B.

In the diagram, with the pair turned horizontal (connector oriented up, looking at the pins), Solenoid A would be on the right of the pair. Pin 1 is left, pin 2 is right.
 

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Discussion Starter #6
Thanks,

The manuals refer to them a single and dual linear solenoids, but don't say which is Shift and which is Pressure.

One is a Shift Solenoid and the other is a Pressure Control solenoid.

What i'm asking is which one of the solenoid assemblies is the Shift Solenoid and which one is the Pressure Control Solenoid?

AND

Assuming on the one that has 2 solenoids together in the same unit there is an A and B.
On the assembly that has 2 solenoids in the same unit, which one of those solenoids is A and B? They seem to have color coded connectors.
 

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Sorry, #7 in the diagram is the clutch pressure solenoid with A/B pair. It can be tested as described previously. Sol A is the upper one. Pin arrangement is as described previously.

Shift Sol A is under the cover that the clutch pressure solenoid is attached to. Link shows the location (upper left). You might have to select the “see more” button.


Reviewing the manual again, the only check given for Shift Solenoid A is using the HDS and checking for a click.

Rockauto has the solenoids and shows color coding.

Sorry for the mix up!
 

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Discussion Starter #8
No problem...I think I got it figured out. I don't know why there's not more info about this available.

113284
Check out this diagram I created and let me know if you think it's correct.

Thanks for you help!!
 

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Nice diagram.

Except for part numbers, confirming what you've labeled for pressure sol A/B is correct.

The shift sol parts diagram is confusing because of the crossing lines. Looking straight at the sols, the factory manual shows sol A and B on the left with A located above B. C and D are on the right with C above D. (The parts diagram appears this way.) Confirming the sol A connector is brown, sol B connector is black.

Also, found a section in the factory manual where you can check resistance between the shift solenoid pin and ground. Should be 12-25 Ohms. You can also supply 12V positive to the pin and check if it clicks.

Appreciate your updates and diagrams. Would be great to see what you find and the fix.
 

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Btw, if you're going to keep your X, the factory manual is excellent. You can get a CD for $35-45 (brand is Bishko). Check ebay or Rockauto.
 

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Discussion Starter #11
I pulled off he pressure control solenoid and shift solenoid A and tested them with a battery 12v And they all click and I did an ohms reading and the shift solenoid shows 16 ohms, and the pressure control solenoid shows 5 ohms on both brown and black connectors.

Also I pulled the tubes with screen and the screens did not appear to be blocked.

What should I try now?

One guy suggested blowing air thru the system to clear out any debries that may be causing blockage.
Do you know how to do this? Where to connected tubes to flush the system? Etc

Also, what’s good to clean the solenoids?

Thanks for you help.
 

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What's the condition of the fluid, and have you returned it to the proper level? If the fluid's dirty, a drain-and-refill is the best thing you can do hands-down (well, other than getting the level correct). It can be a bear to do a "real level check" as you have to drive the vehicle until the tranny's at full operating temperature, and then find a level place to park it, then shut it off and check the fluid level within (IIRC) 30 seconds. A workable solution is to drain the fluid, and put three quarts back in. You'll almost certainly be within a half-quart of "perfect" (and probably a lot closer than that unless you're draining it sitting perfectly level, which I've never been able to do). ;-)

You might be able to clean and re-use those solenoids, but if it was my MDX, I'd just swap 'em out. Yes, you will spend a bit more doing it that way, but you'll likely avoid some do-overs on the work you've already done that way.

Oh, and make VERY certain that you get those little tubes back in the right holes.
 

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Good that the solenoids all checked out electrically. If you still have it apart, you might look in the pressure sol ports and check that the rods actually move with the click.

Cleaning the sols with carb cleaner or brake cleaner could work. Something that evaporates. Don’t squirt any in the trans. Relube with clean trans fluid and keep them clean.

You might check that the wiring and connectors to the pressure sol are good. Wondering if they’re getting a signal to fire or the signal is not turning off resulting in getting stuck open.

Not sure about blowing air into the system. Saying that bc not sure you could accidentally jam something and if the area around the engine or trans is dirty, you could accidentally blow back dirt into the solenoid cavity.

Since you found that the solenoids work, just curious if you corrected the fluid level and tested it before taking it apart. If not, you might just reinstall everything, reset the code, and see if it comes back. Wondering if the overfill could have been affecting solenoid operation. You could change the fluid too as Habby mentions. Sometimes it’s good to do one change at a time to see if the problem resolves or continues. If these don’t work, change the sols.

Another thing to consider in case you have debris in the system or to minimize the affect of future debris is to install a magnetic, in-line trans filter. Fairly easy to do. It goes in the trans fluid return line from the radiator to the trans. There are posts on it and you can look up the factory trans cooler install instructions to find out which lines are which.

 

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Discussion Starter #14
What's the condition of the fluid, and have you returned it to the proper level? If the fluid's dirty, a drain-and-refill is the best thing you can do hands-down (well, other than getting the level correct). It can be a bear to do a "real level check" as you have to drive the vehicle until the tranny's at full operating temperature, and then find a level place to park it, then shut it off and check the fluid level within (IIRC) 30 seconds. A workable solution is to drain the fluid, and put three quarts back in. You'll almost certainly be within a half-quart of "perfect" (and probably a lot closer than that unless you're draining it sitting perfectly level, which I've never been able to do). ;-)

You might be able to clean and re-use those solenoids, but if it was my MDX, I'd just swap 'em out. Yes, you will spend a bit more doing it that way, but you'll likely avoid some do-overs on the work you've already done that way.

Oh, and make VERY certain that you get those little tubes back in the right holes.

Thanks for responding.

To answer your question yes I did drain some of the fluid and added a quart and a half to bring it to the specified level. The problem still persisted. So I drained it all and replaced with 3 new quarts as explained below. The fluid doesn’t really smell burned now. Maybe a little dark from the old fluid mix but mostly cleanish red.

I took out all four of the shift solenoids and the dual pressure control solenoid A/B and tested them all with a 12v battery and they all clicked ok. I even cleaned them out with brake cleaner while clicking them open n closed n cleaned the tubes n screens, they were not clogged.. Then I put it all back together and then drained the fluid and put 3 quarts (2.9) new fluid in. Started it and put it in all the gears and all the gears engaged and worked, but after it had been running for a few minutes then it stops going into any of the gears and just revs and the car won’t move. If I turn the car off a let it sit for a minute and start it up it will go into all the gears and move the car but after a couple minutes it revs n won’t engage any gear. And this repeats over n over when I shut off the car for a minute and restart it, it shifts into gears and it moves then stops moving n just revs after a minute or so. Etc...

So it seems for some reason whatever isends pressure to the gears stops sending the pressure. I’m assuming the needed pressure to change the gears goes away after a minute or two causing the car to stop accelerating by not engaging any of the gears. What would cause that? One minute the gears work the next minute they don’t. Bad pressure solenoid or something else?

The battery was disconnected while I worked on it so the trouble codes went away and surprisingly after I drove it n the it stopped moving the trouble codes did not come back even though I was having the same problem.

Another thing is for a few months it occasionally makes this fluttering noise (like shuffling card noise) when first running in the morning but doesn’t do it all the time n it goes away after driving it a mile. Any idea what that is?

Please help!

Help me obi-wan kenobi. You’re my only hope.

What do I do now? Replace the pressure solenoid?

I’m stuck waiting for answers . Please respond ASAP!!! Nothing gets done til I hear from you guys!!
 

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My gut is telling me that the pressure control system is the problem, and the pressure control solenoids would be the most likely suspect. Since they do seem to move and check out OK, it casts some doubt on that option, but they could be failing "thermally" (the clearances when hot are going to be different than when they're cold).

There are a lot of other moving parts in that transmission that could be causing the problem, but your previous codes do point toward the pressure control solenoids (the A/B unit - "C" is for the torque converter lock-up mechanism, I believe).

What I'd do if it was my MDX... First, I'd pour 10 ounces of LubeGard Platinum in it. That's just because I've "fixed" a couple pretty badly behaving transmissions with the stuff. I'm not a big fan of snake oil in general, but this stuff does seem to work well for Honda and Subaru transmissions. Plus, it's cheap and easy - not really anything to lose. Just pour it in, and drive around for a while and see if it shifts better.

If not, I'd swap out the A/B solenoid unit "just because". It might not fix it, or it might. Compared to replacing the tranny, its chump change (and effort).

The only other thing I'd add is that having a Honda Diagnostic System kit on a laptop could be VERY helpful, as it allows you to see pretty much everything going on inside your tranny (including the position and status of all the shift solenoids and pressure control solenoids). That can be a little fiddly, but it's invaluable in a situation where you're really looking for a "deep problem".
 

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You might need Chewy or to beam Scotty down.

Sorry to hear it didn’t work so far. Besides what Habby says, if you’re going to try more DIY, you might want to get a factory manual. There are electrical and hydraulic circuit diagrams.

Also search the forum and net.

Might be time to call around to some shops and at least pay for a diagnostic service. I would stay with shops that specialize in Acura and Honda. If not word of mouth, try Yelp.

That flutter might be the cause of all the issues.

May the force be with you!
 

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Discussion Starter #17
Thank you so much for the replies.

I went n got a used pressure control solenoid a/b and the pressure control solenoid c (on top of engine - torque converter lockup solenoid - was told this is what holds the car in gear) and cleaned and tested them and swapped them both out and drained the fluid and refilled and drained it again and refilled (fluid is pretty clear now) and still problem persists, although it did seem to shift a little better while cold like normal. I was able to drive down the street n get up to 40mph-ish. And it did seem like it was trying to stay in gear or grab more, but still starts reving after heats up. I'll try it again today n see what it does.


I did call a couple places to see what they had to say. One guy said the torque converter was wearing out causing the internal filter to clog and needed to be rebuilt. Another guy said similar that the internal filter is clogged not letting the fluid circulate causing lack of pressure. Neither suggested doing a tranny flush because they said it would bring up all the other debris inside and circulate it thru the system and cause clogs or other problems. (isn't that the point of flushing the system to get all the debris out?) They may be right but I don’t trust any of these places cuz they’re out to make money.

However, it does sound like the car runs fine when cold and after heating up for a few mins won’t hold in any gear and just revs. That’s the problem in a nutshell. But when cold works in all the gears, or at least up to however fast I can get it before it heats up n stops moving, which is around 3rd or 4th gear aka 3k rpm or 30-40mph.

I could be wrong, but it doesn't seem like its something major, I only say that because I changed the fluid every 10K miles instead of every 30K miles, and it was working perfect for the most part. Occasionally, it would rev when shifting into gear while driving once in a blue moon for about a 2 seconds then go into gear n drive normal.

So, I want to restate how the problem started again...I was driving down the freeway, about 100 degrees out, had cruise control on and ac on, going about 75mph and it started to mildly jerk a little, had been driving it for 20 mins, then started to rev n slow down, pulled over turned it off, started it, shifted ok then started reving after a minute or so of driving. Got it home, checked the fluid - looked over full on dipstick and smelled a little burned, checked the codes, had the p0752 and p0747 (shift sol A stuck on and pressure cntrl sol A stuck on)(the guy at the tranny shop said those codes don't necessarily mean what they say, he says the computer told the tranny to do something and it didn't work and so it threw those codes which he said was a result of the torque converter going out causing the filter to get clogged).

Something else I want to restate...when the tow truck guy hooked up the car to pull it onto the truck bed, he didn't take it out of park, and started pulling it with the wench and my car made a clicking sound twice before the guy stopped then go into the car without releasing the tension from the wench and pulled the car out of park into neutral. Could this have thrown off all the gears in any way? because I noticed a couple times when trying to shift from park to reverse it has made a gear rattling noise for a brief moment. but goes into park fine n stays.

The only thing I didn't do was when I pulled out the 4 shift solenoids and checked them all, I noticed the black one in the lower right corner, which is supposed to be the torque converter solenoid, seemed to move a little sluggish, but it could've just been my own observation in error, but when applied battery to it, it kind of moved a little slower than the other ones or at least it seemed to me, but i did clean all of them with brake cleaner and did it while opening and closing the solenoid with the battery power so made sure fluid ran through ok. But, I didn't change this solenoid because it wasn't the shift sol A that the code mentioned. Don't know if it would make any difference or not.

Any other suggestions?

How do I get or download that Honda Diagnostic System kit on a laptop n how do I connect it to the car to get readings?

Also, did one of you share 3 links to some info and diagrams about this setup? I thought I saw them once but can't find them now?

Ok, That's as much as I can fit in this post now! lol

All your help is so appreciated. I'll buy you guys pizza! I'm so stressed out. Need to get this thing fixed.

Thank you thank you thank you

Please let me know what to try next. Thanks!
 

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Discussion Starter #18
In this diagram, which solenoid is called what? and what does each do?
I think the top left is shift solenoid A, then to the right top is shift solenoid B, then to the bottom left is shift solenoid C, then bottom right is ??? n what does it do? Actually what does each on do specifically? what do they control?
 

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Don’t know about free manuals. I suppose you can check this forum and online. The trans section alone is 200+ pages. If you’re reluctant to throw even minimal money at it, maybe it’s time to sell.

There are a lot of valves and pressure switches. Your mech might be right. I recall a guy on the forum had his trans rebuilt or bought a rebuilt for 1st gear flare problems from a place called ozmotive in San Jose. Might be worth researching.

If the trans acts up when warmed up or hot, only a couple other things I could suggest: 1) check the solenoid resistance and clicking with it hot. Maybe the coils are starting to break down. Probably easier said than done. Possible for the AB clutch but harder to do for the shift sols. Dip them in hot trans fluid???

2) Since two of the shift sols are the same you could swap them to see if you get a different result. (Do one change at a time.)

You sure you assembled it correctly? O-rings were in decent shape? Shift linkage is correct?

Sol A,B, C are shift. You’ll have to look up Sol D.

You might have to bite the bullet for a trans repair or sell the X.

Good luck!
 
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