Here we go... First time poster and long time reader.
I bought this car back in 2016 and had to do an AV6 swap in 2018. It took a few months, but finally took care of all DTC codes in the car and enjoyed driving it until about a month ago when the P1768 popped on. A/T Clutch Pressure Control Solenoid A Ohmed out at 5.9 and clicked under battery voltage. So I disconnected the B connector from the PCM and checked for continuity on B8 and B17. B8 had no continuity but B17 had continuity. Here is the question, when I checked the wires, the connector for the Solenoid has a Red and White wire, but at the PCM, B8 and B17 are not those colors. Looking for information on whether this matters and if the wires are in fact different, where do they connect?

 

Their should be 2 of the same solenoids you can swap and see if it throws a different code, also check your grounds. A faulty ground sometimes throws that code

 

Perhaps you were checking the connector backwards? Check Page 11-36 in the service manual for wiring descriptions...

my understanding of the tests on page 14-304 is as follows:

1. (Step 2) check the solenoid: disconnect the solenoid and make sure there IS continuity between both terminals on that solenoid
2. (Step 3) check for a short in the wiring to the solenoid: LEAVE THE SOLENOID DISCONNECTED and check that the other end of the wires running to it DO NOT have continuity to the ground, if they do, then then are touching ground somewhere (a short)
3. (Step 6) check for an open circuit in the wiring to the solenoid: CONNECT THE SOLENOID end and check that the PCM end of the wiring measures the same amount of impedance (no additional impedance is being introduced by the wiring to that solenoid, such as a damaged wire that's NOT touching the body OR simple the connecter isn't connecting the wires to the solenoid)
4. Further testing is to check for issues with the PCM, loose, open or shorted wiring there or simply a bad PCM.

You stated "B8 had no continuity but B17 had continuity."

So if you were indeed checking the correct wires, and the solenoid was DISCONNECTED to the other end of the wires, B17 wire is shorted to the body of the car somewhere...

By the way, when I did my AV6 Swap, I plugged in one of these solenoid and when I when I did so the connector somehow was allowing the wire to be pushed out of it's connection, leaving it open, so that can happen.

 

I have been super busy lately, but had the opportunity to put the car back together with a junkyard A/B clutch pressure control solenoid. My first inclination was to completely pull the wire harness and remove the sheathing while I had everything out, but instead I ended up playing around with the intake manifold. I did some massive cleaning of the EGR port, etc. I now need to order new gaskets, but that is another story.

I checked the grounds for continuity and they all worked (G101, etc.). Once I put everything back together and ran the car, the only code still present is the P1768, so I consider this as having done the "wiggle" test. Also, I believe that since a different A/B CPCS shows the same code, it must be in the wires (hopefully not a bad PCM!! But I need to complete the troubleshooting with everything put back together) I am going to go back in tonight and check the wiring and connectors again, then check voltage on PCM connectors with ignition in the "ON" position. My only regret is that the Shop manual doesn't have the nice electrical wiring diagrams that show the entire circuit on one page. It seems there should be an electrical splice in the line and not a direct connect from the PCM terminals to the solenoid?? Wish me luck finding something,,,

 

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Latest update on this. Car is presently taken apart again, but the wiring harness is still in. I finally located the wiring diagrams!!! (google images search, took a bit of time to find a complete circuit for engine/transmission - but MUCH better than the Shop manual)
Just want everyone to know that MOST of the transmission solenoids are indeed a direct connect from each positive/negative wire back to the ECM/PCM. Therefore any wire opens or shorts will be located in the harness. Funny thing is that after having done multiple visuals, I have no clues as to damage to the harness or anything obvious. I will let you know when I find something, it will take awhile to go through and untangle everything to trace those wires.









***Disclaimer - these images have no indication from where they originated. I am guessing they are public domain, if any one on this forum knows otherwise, please advise and I will remove them.***

 

So this is where I am presently stuck. Does ANYONE have any suggestions or have seen or heard of this before? I even found one video troubleshooting the PCM voltages and it cut off before the person found the problem. Now I did some research online and seemed like a simple fix. Let me say it is not. I have swapped the A/T Control Pressure A/B solenoid out with a known good part. Ohmed the wiring and found it to be on spec Checked for continuity in wires from PCM to solenoid. Checked for voltage coming into PCM and found11.53 volts. Ohmed the PCM ground and they are good. And nothing works. As soon as I turn the key on d5 light flashes. Car doesn't even have to be running. If you do drive it the car is stuck in limp mode. Does anyone have any suggestions??? I think I have told you guys everything.

 

Thanks for this response UA5_6MT, I recently checked chassis, engine, and all engine compartment ground points and the all show battery voltage (12.5V). I know that is a little low but I have had the car in the garage for a few weeks now. I even cleaned up several wire harness ground points in the process...

 

Have you rechecked your CEL codes? After all the above mentioned work?

 

Hello whitetiger5, just got back frmo the garage and I pulled the battery 3X. After each time, I moved the wires in the A and B connectors to see if it would create a different code. Unfortunately the same code appeared each time, "P1768 Torque Convertor Clutch Solenoid Circuit B issue". I think this is my scan readers own way of reporting the code, but everything I read indicatesthat p1768 is an A/T CPCV A circuit problem for our cars. So I will continue to research this until someone has an idea about where the electrical issue might be. I am afraid it can literally be a short anywhere in the car at this point.

BTW- does anyone know the Duty Cycle for this solenoid? (A and B) If I now the target voltage, I can check it against what the PCM is sending on the positive circuit versus what is coming back on the negative circuit. I have two DVOM's and can take readings with the key in the on position. If I can eliminate this, I can then concentrate on voltage between fuse number 6 and the PCM (which at 11.5V seems a bit low, read at the D5 connector...) I believe this might be a voltage drop issue.

 

First, here is a video that, although is cut off at the end, details the steps for checking the A/T Clutch Pressure Control Solenoid Valves A and B and their circuit:

Second, This document details exactly how the A/T Clutch Pressure Control Solenoid Valves A and B work:
https://atracom.blob.core.windows.ne...2007_05_22.pdf

Last, this link further describes how duty cycle and pulse width modulation are used by the PCM to operated transmission solenoids in general:
https://www.freeasestudyguides.com/t...-solenoid.html

Although I have not found a solution for my issue, hopefully this will help others with all of the mysterious Honda/Acura transmission issues and possible causes that lead to transmission failure, besides the obvious engineering concerns. (I have heard that the engines are too powerful for the transmission design, etc.)