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Discussion Starter #1
Hello
I have an 03 mdx was working fine then one day on way home the engine started to rev while the speed slowed down. I pulled over n let it sit for a minute then it drive normal for about 30 seconds then did it again as if the car is not staying engaged in gear. I pull over it cools off for a minute then drives ok for about 10 to 30 seconds then skips again. I changed the tranny fkuid with Honda fluid three times n still same scenario. After it runs or warms up for about a minute or two it just revs after that n won’t move.
When draining n refilling I didn’t notice anything in the fluid n I drained it thru a screen.
I always changed the trans fluid every 10k miles with honda fluid.
Originally it gave me two codes that said
Shift sol a stuck on
Pressure sol a stuck on
I changed them out with used ones out of the junkyard
Then I used a diagnostic tool to do some tests
The clicking tests shoes all the shift n pressure sols n tcc sol clicked on n off except the pressure sol b couldn’t hear it click on at all but do hear if click off (strange-not sure if it’s supposed to be engaged in Park or not)
Then did pressure sol test with car running and both pressure sol a and b test said sol is normal but when I did the test on pressure sol c it said “test stopped car is no longer in drive.”
So I’m not sure if something is wrong with pressure sol b or pressure sol c or both.
All the other tests I did like indicator tests when car is in different gears showed what they’re supposed to be.
I did read somewhere in the manual that said if the car is slow to go into gear it meant that pressure sol c was going bad. N this is a symptom it does shift gears slowly when it warms up or runs for a few mins, so slow I can hear the gears clinking.

Any help is appreciated.
285K miles
 

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There are a lot of reports about the pressure sensors / switches going bad with age (and 285,000 miles qualifies!). Solenoids can fail in a way that won't necessarily throw a code, or prevent them clicking. The main failure mode seems to be getting gunked up, though your impressive maintenance program would seem to minimize that.

The other thing I'd do - even just having typed a semi-warning about "snake oil" would be to add some LubeGard Platinum. I have "fixed" a couple badly behaving transmissions with the stuff, and it gets some impressively glowing reviews from obvious "real reviewers".

And just to check the obvious - you're absolutely sure that the level is right (engine warm, shut off, check within 30 seconds)?
 

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Discussion Starter #3
Thx
Another test I did was running the shifter thru all the gears n on the tool it shows me which solenoids r on n off in that gear, but I noticed that the tcc solenoid always stays off when shifting thru the gears. Is this normal? Is it supposed to be turning on only turns on at certain speeds?

Again I also want to mention that when performing the cpc solenoids test when the car is running, both a and b cpc solenoids say normal but when testing cpc solenoid c, it says “test stopped car is no longer in Drive”” (the test says to put the car in Drive for the test).
What could be causing this?
 

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Great job diagnosing.

Excerpts (paraphrased) from the factory service manual that might help you with sol C. (I have a paper copy so not so easy to post whole pages.) With your description and what the manual states, I would suspect sol C and/or a filter on the ATF pipe mentioned below.

While installed:
#8. Disconnect the connector to sol C.
#9. Check resistance of the solenoid - should be 3-10 Ohms. If out of standard, replace sol C.

#15. With the solenoid removed - connect battery + to terminal 1 (orientation is facing the solenoid connector, with the one rib over each connector vertical, #1 is on the left). Battery - on #2, toggle the connection so the valve moves.
#16. If the valve binds or moves sluggishly, or doesn't work, replace sol C.

From #18, it appears that when sol C is removed, there is a ATF pipe that should stick out 0.3 inches (7mm). That pipe has a filter on the end that is sitting in the trans. Maybe it's clogged.

Btw, what diagnostic tool / model are you using? Sounds handy.

Good luck!
 

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Discussion Starter #5
Thx so much
I did replace n test the cpc sol c n tested it beforehand
I wondering what else it could be that would make the running test say “test stopped - car is no longer in gear”
When performing the test it says to puts blocks under the wheels rev the engine then let off then put the car in drive while holding ur foot on the brake n after putting car in D it says testing sol for 30 seconds. then it says to let ur foot off the brake n at this point is where it tells u that the cpc sol is good or not , but in my case as soon as I put the car in D gear it goes straight to saying let ur foot off the brake n then says test stopped car is no longer in gear.
It only does this when testing cpc sol c.
Both cpc sols a n b says test completed solenoid is normal.

Any ideas?

The diagnostic tool I used was the Matco Maximus.

Also could you please read my first post again n answer the question about the tcc sol?

Thank you for the help.
 

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A few items from the FSM re operation:

Pg 14-37:
Clutch Pressure Sol C and TCC operate at lock-up condition.
Pg 14-22:
In D3, lock-up operates in 2nd and 3rd gear
In D4, lock-up operates in 2nd-4th gears
In D5, lock-up operates in 2nd-5th gears

Stall speed for the TC should be 1950 RPMs

Re Shift sol A, B, C, and the TCC. The TCC is shown as D in the figure. Page 14-182-184:
#17 Resistance of all 4 are to be 12-25 Ohms. Replace if out of standard.
#18 If they click, they are good. If no click, states to replace.
#21-25 Use new o-rings on the these. The order of install of the solenoids is shown as B, TCC, C, A. At #22, there is a note to not install C before the TCC. There is a statement that if C is installed before TCC, damage to the hydraulic system may occur. Sorry it doesn't say much. There is no explanation of what gets damaged and how to recover.

In case helpfull, those 3 pipes under the clutch pressure sols A/B also have a filter. Filter end goes towards the trans.

Good luck!
 

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Discussion Starter #7
Thx again. Yeah I already checked n cleaned all the screens n solenoids n tested the ohms n all click. Everything is normal.

FYI the reason it says to install shift solenoid c after the tcc **** solenoid is because each solenoid has a small bracket that sticks out for the screw to secure it n both brackets over lap to use the same screw and putting the wrong one on top of the other won’t seal them correctly in the port hole.

Question 1:
Any idea why the cpc solenoids (pressure solenoids) engine running test would say “test stopped car is no longer in D” when testing cpc solenoid c as soon as I put the car in D for the rest?

Question 2:
Does the tcc only engage when the car is running at high speeds (not at idle speed)?

Question 3:
When testing the clicking of the cpc solenoids (pressure solenoids) via the diagnostic tool, cpc solenoids a and c click on n off normally but cpc solenoid b can’t hear it click on but do hear it click off, any idea if cpc solenoid b is supposed to be on in park or does this indicate a problem?

Fyi cpc solenoids a n b are a one unit dual linear solenoid.

Please number responses.

Please help thanks
 

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Hope this helps, I’m reading across multiple pages and diagrams. You should know I have never dug this far into a trans and how it works. Like to learn and learned a lot though just looking through this.

Unless another member can post a number of pages, youbmight want to buy a factory manual. I’ve seen them time-to-time on-line for $40-$60.

Q1: No firm idea. In D5, shift sols A/B/C should be on for first gear and during shifting to 2nd. After shifting to 2nd, A/B should be on. Only Sol B for shifting to 3rd. B/C on for driving in 3rd.

Q2: TCC works in conjunction with Clutch pressure sol C to lock up the torque converter. PCM controls it.

Q3: No description for park but in Neutral, CPC are off. CPC B comes when shifting to 1st from neutral. For next gears, CPC A and B toggle to shift gears.

Far from sure but from your description, seems you have some sluggish CPC or shift solenoids.
 

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Discussion Starter #9
I mean is the tcc solenoid supposed to engage when the car is running (or not running but with key on) when sitting at a standstill with your foot on the brake while shifting thru different gears?

I notice that when sitting at a standstill with my foot on the brake car running shifting thru each gear, the diagnostic tool shows me each solenoid turning on n off but the tcc solenoid never turns on. Is this normal?
That’s why I was asking if the tcc solenoid only engages when the car is being driven at high speeds, or is it supposed to engage even at a standstill while shifting thru each gear.
If it is supposed to be engaging, what tells it to engage or causes it to engage? So I can check that.

Thx for the help j
 

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The TCC solenoid engages at speed, when the conditions are such that locking up the torque converter is called for. You're not going to see that happen until you're at highway speed.

I don't recall the exact parameters, but will find and post them if the above doesn't tell you what you need to know.
 

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OP probably figured it out already but to close out the his last question, FSM shows lock up testing to be done at 55mph for 2 mins. (Not that is takes 2 mins to lock up but at steady speed).

Manual further has descriptions when the accelerator pedal is at 0.8 volts, lock-up occurs between 48-51 mph. At 2.25V, 89-93 mph. At 4.5V, 105-109 mph. I take those as light, med, and hard acceleration.
 

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Discussion Starter #13
Awesome thx now I can scratch that off my list of not working things.

I would assume the same about the 3rd n 4th gear pressure switches since they don’t show a reading either when testing while car running not moving in the driveway while switching through all gears.???

I still don’t understand what could be causing the car to not move after it’s been running a few minutes. After it sits not running for a while, it shifts gears n moves fine but after running a minute it won’t move. Hmm what else could it be or could I check?
 

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its all the debris off the clutch plates floating around.after the car runs for a bit the debris plugs up all the little screens in the transmission.ive got a 2003 mdx stored in the shop that does the exact same thing.will move when first started but after a couple minutes it wont move.
 

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this guy does a complete tear down of a mdx transmission.watch the whole vid its really good.around the 25 minute mark is likely your problem.
 

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Discussion Starter #16
Thx plot hound

What about the fact that I drained n refilled the fluid three times thru a screen n it’s clear n no debris in the screen or drain pan?

Also please read my previous posts about all the tests I did n give your thoughts.
Thx
 

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i did the same drain and fill with both the wifes daily driver and the spare mdx ive got stored.even added lubeguard to the mix with the same results.car will drive about 300 yards then nothing.ended up getting the transmission rebuilt in the daily driver and the spare is gonna get rebuilt in the spring.gotta get 1 more winter out of the daily driver.
 
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