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  #21  
Old 04-12-2020, 05:41 AM
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The code P0751 is for the MV1 solenoid shown in the image below.



The MV1 solenoid is activated in Park (to engage the F-brake so that the running gear is held stationary) which would explain why failsafe is activated before you even engage drive.

If the transmission were in the car, I would have recommended you try swapping the MV solenoids around to see if the problem moved with the solenoid. If not, it would point to a wiring fault.

With the transmission out of the car, all you can do is check the solenoid’s winding resistance (around 26-28Ω), see if it clicks on and off with 12V applied to the terminals, test the continuity of the internal wiring loom and the continuity of the vehicle wiring harness, as the code is saying that the solenoid is disconnected (open circuit).

If you do a continuity test on the internal wiring loom between pins 8 and 16 at the 16-pin plug (assuming the internal wiring harness is still connected to the solenoids)



and then also test the continuity on the vehicle wiring harness between pin 8 at the 16-pin plug and the corresponding pin 38 at the ECU connector, and then pin 16 at the 16-pin plug and pin 21 at the ECU connector on the vehicle









The pin numbers are marked on the connectors, but you may need a magnifying glass.

Phil
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  #22  
Old 04-13-2020, 12:28 PM
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What a fantastic and informative post. This gives me exactly what I need to pinpoint the problem.


The second time I pulled the transmission I ended up having to break apart some of the plastic from the coupler for the internal wiring loom because it refused to separate. The damaged coupler didn't seem to compromise the connectivity and the plug appeared to fully seat when I reinstalled the trans, but now I'm wondering if this could be causing me issues.


Here are the most recent set of codes I pulled off of INPA.

Error Codes: 49, 16, 83, 34
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Just as a reference; here is a link to a video I took of the transmission shifting from a dead stop and then going into safe mode. The fail-safe kicks in at 52 seconds into the clip. Other than the fail-safe, it seemed to behaving quite normally.



https://photos.google.com/share/AF1Q...JDcjRaWlFTcjRB


I hope to be able to get out to the garage and bench test the solenoid this evening, once I finish up work for the day.


Thanks Again!





Last edited by hammerdownineffect; 04-14-2020 at 08:56 PM.
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  #23  
Old 04-13-2020, 12:33 PM
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Quote:
Originally Posted by TriX5 View Post
Can you post the error codes? Sometimes they are pretty cryptic but sometimes they lead you right to the source. I read German but not very good at deciphering the more cryptic messages, either way, let's see what you have. (By the way, FCP Euro seems to be ope and they are not too far from you in CT.)

Hi TriX5,


Here are the 4 codes I pulled off of INPA:


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I had 5 codes previously from my first trans install but these 4 are the most recent set. Let me know if you want me to share the other 5 codes too.



Thanks so much for your help!!!
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  #24  
Old 04-13-2020, 09:01 PM
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The last two indicate an open circuit for the temp sensor and for the trans mgt. The first two are the valve and the gear monitor (i.e. which gear is engaged)

Maybe a wire got damaged or the plug did not engage properly? I have seen posts where pins got pushed in to the connector body and so impossible to connect properly.
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  #25  
Old 04-13-2020, 09:25 PM
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Quote:
Originally Posted by TriX5 View Post
The last two indicate an open circuit for the temp sensor and for the trans mgt. The first two are the valve and the gear monitor (i.e. which gear is engaged)

Maybe a wire got damaged or the plug did not engage properly? I have seen posts where pins got pushed in to the connector body and so impossible to connect properly.

I'm really wondering if I somehow damaged the pin connectors trying to get the coupler to release. I had to split sections of plastic from the outer coupler to be able to unscrew the two halves. They appear to reseat normally but I'm going to take a closer look at those pins to see if anything was damaged.


Thanks a ton for referencing those codes for me!
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  #26  
Old 04-15-2020, 01:19 AM
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Hi RRPhil,


Sorry it took an additional day to perform these diagnostics, a wind storm hit our area and we ended up loosing power.


Anyway, I was able to finish up this evening and here are the results.


I applied 12v to the MV1 (as well as all of them) and they all clicked on/off.


See Video in Link: https://photos.app.goo.gl/fDEYs5iFAn8sg1qZ9


I checked the resistance of the Solenoids and MV1 came in at 15.9 ohms, while SV2 and SV3 measured at 16. Interestingly after I checked function by applying voltage SV1 measured at 16 while MV2/MV3 went up to 16.1 (probably more of a variance of my multimeter than anything else).


Note: I did end up swapping the solenoids between MV1 and MV3 so it could help further pinpoint the issue if it throws a code again.

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I checked continuity first from the plug at the MV1 solenoid to the 16 pin plug and both pins checked out. Then I checked continuity from the 16 pin connector to the harness on the TC and those checked out as well. Finally, I plugged in the 16 pin harness into the back of the trans and confirmed that I had continuity from both wires at MV1 all the way to the TCM harness. So, unfortunately I was not able find in issue with the electrical connection.


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Finally, I performed an air check on the A/B clutch drum assemblies by placing it in the pump stator and applying 40-50 PSI of pressure through 2 different passageways. I've marked the in the photo below.



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The passage marked "2" tests the A Drum and I'm told it confirms that everything is sealing by essentially trying the launch the clutch drum assemblies out of the stator when air pressure is applied. Everything seemed to check out with this test.


The passage marked "1" tests the B Drum and confirms function by moving the clutch plates when air pressure is applied. Even though my clutch plates were moving their was air escaping from what appeared to be the "2" passageway. I'm told that there shouldn't be any air escaping during this test. Can you confirm if this is true? If this is true could this mean that there may be a potential issue with the fluid pump?


As an aside, I also noticed some gasket sealant had bled over into some of the passageways around the pump stator. It wasn't a lot of excess sealant but probably enough to interrupt some fluid transfer.


Sorry for the long post but I wanted to offer as much detail as I could about my current status. Unfortunately, all the electrical tests for the MV1 passed but I'm wondering now if there if this air leak around the pump stator means anything to you.


This has been a HUGE project and I'm hopeful I might soon see the light at the end of this tunnel. Thanks again to you and all the other contributors on this board!
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  #27  
Old 04-15-2020, 10:18 AM
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Is there a way to bring the car and the trans together and make only the electrical connections? I.e. just provisionally plug things in without mechanically mating trans to motor and run INPA to see if the circuit interruptions re-occur? I know that maybe a bit tricky but it would help as I think that circuit interruption detection isfairly reliable. A bit like your light bulb going out :-) P.e. I had an error saying Evap valve open circuit and sure enough, the voltmeter showed open circuit, replacing it fixed the problem. Electrical problems can be a bear :-)
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2006 4.8iS Le Mans blue/cream int./black headliner, SOLD in 2012 sadly...

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  #28  
Old 04-15-2020, 11:01 AM
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Quote:
Originally Posted by TriX5 View Post
Is there a way to bring the car and the trans together and make only the electrical connections? I.e. just provisionally plug things in without mechanically mating trans to motor and run INPA to see if the circuit interruptions re-occur? I know that maybe a bit tricky but it would help as I think that circuit interruption detection isfairly reliable. A bit like your light bulb going out :-) P.e. I had an error saying Evap valve open circuit and sure enough, the voltmeter showed open circuit, replacing it fixed the problem. Electrical problems can be a bear :-)

It wouldn't be a problem to reconnect the 16 pin connector to the back of the trans since this is what I did when I performed the continuity test. Should I clear the present error codes, turn on the ignition and see if anything new pops up? Do you think I also need to connect the shift coupler as well?



One strange thing I found when I checked continuity was that each of the two circuits showed a different resistance. One circuit showed .3 ohms, the other .2 ohms. I retested many times and still got the same measurements. Not sure if this is relevant at all but just thought I'd throw that out there.


Have you ever heard of air testing the A/B drum like I posted above? If so, do you know if it is normal air leaking when testing the B drum?



Thanks for the new test ideas!
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  #29  
Old 04-15-2020, 02:17 PM
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It’s probably easier to get a small sheet of (say) acrylic (we call it Perspex in the UK) which is very flat, drill a hole through it for your air blow gun, and then hold it over and pressurise the relevant chambers on the underside of the maincase where the valve body assembly sits. This will test the whole clutch hydraulic circuit. I’ve shown on the image where the feed chambers for the A & B clutches are.

Phil
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  #30  
Old 04-15-2020, 03:08 PM
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Great! I probably have something laying around to do this test.



How much air pressure/PSI should I be utilizing and what kind of response am I looking for when I apply the pressure (i.e. how do I tell if it is functioning properly verses something is wrong)?



Also, do the A/B drums need to be installed for this test?




Not sure if my post about the A/B clutch assembly test I did made any sense. Do you know if the air leak I get when testing the B drum is a sign of anything wrong?


Thanks again!
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