Transmission , codes P1731 and P1732

You changed the actual gearbox itself, not the PDK control unit under the dash, correct?
Having two sensor codes at the same time I would check the harness from the control unit out to the gearbox. They use a low voltage and it wouldn't take much corrosion or pin fitment to cause a failure. I would also verify the signal from both displacement (1 & 2 as you have codes for both) sensors outside the gearbox. This should help you locate the correct wires. Also be sure the shop is using the latest version (or at least version 2) of PIWIS, the older versions don't work well on the newer vehicles.

Hello Steve, thank you for your answer.

Actually we changed only the pdk gearbox not its Control Unit.
Because before bying the new gearbox we have checked the Control unit and it was dry and clean. We also checked and cleaned the harness.

We thought that the sensors p1731 and p1732 are inside the gearbox and we couldn't reach them. Where can we find the two sensors ?

Do you think that it can be related to the control unit ? Should I change it ?

Thank you a lot

Hello,

Kindly send me again the image in good resolution because it’s too small and not clear. Thank you very much

HMM, that should have been a large diagram. Something must have messed up the upload. Try these.

Thank you sir. I ordered the pdk control unit today. I hope it will fix the issue.

Hello,

I found these wiring diagrams and wanted to help.

Check out the transmission wiring diagrams (Below)

Please let us know what you find. We are interested to see what it is.

Cheers, Ken

Hello,

Thanks for your help. I will keep you updated about progress.

Hello,
Now after changing the pdk control unit the error p1731 and p1732 have been fixed but we have new errors that we never got : P0846, U0446 and U0456. Guys, help me by any advice please thanks.

P0846 - Pressure sensor clutch 2, signal implausible - Shorted to bat + That would be the Green/White wire on pin 12 from the transmission to the PDK unit. It is reading above 4 volts. Either the wire is shorted to another power wire or the sensor itself is bad.

The U codes are CAN related
U0446 - Body control module - invalid data
U0456 - Coolant temperature control module - invalid data

I would clear the U codes and see if they return. Both could be caused by having the battery disconnected. Or the coolant temp sensor is disconnected.

Thank you so much for your help!

Please let us know what happens.

Cheers, Ken

Hello,

Steve, is the sensor changeable ?

Both information sources say they can be, BUT you will want to test the wiring first. The internal harness in the trans connecting the pressure sensors to the plug may be the problem. Says you pull the pan and the pressure sensors are inside screwed into the trans. You still have the old unit right? Maybe pull it open and check.

Thanks a lot Steve. I will keep you updated

I found solution for this case,

Porsche Panamera Uses ZF Transmission, for P1731 , P1732 , P1733 , P1734 fault codes not required to replace gearbox (PDK) or transmission control unit, Just simply replace following part:

- Sensor Pack (Position Sensor with Speed and Temperature Sensors)
- Part#: 97031708500, Estimated Price is 500 USD.

But before any replacement, make sure your battery life is good, because Porsche is one of the most sensitive cars to over/under voltage situations. So much technology is packed into them, that bad or going battery can and does make funny things with totally unrelated systems.
Everything in the car is controlled by microprocessors and when the voltages get low you get weird signals that can be misinterpreted by the other processors.
If not worked, then try to replace with above sensor pack.

I know this is an old posting, but I’m really curious about how did you fix the problem. Ive run into the same exact troubleshoot, and neither I or the dealer seem to be able to solve it. They’ve already replaced the sensor pack from inside the transmission, but the issue is still present. The vehicle had the same codes you described above, and was jumping into limp mode after about 20 min of driving. Usually after about 1 hour cool off, it ran normally for another 15-20min before the issue reappearing. Any help will be helpful!
Thanks in advance guys

Hello,
I fixed the issue by changing the sensor. Maybe the one that you changed is not good.

I have seen defective sensors before, is the replacement OEM?

15-20 minutes sounds like a heat issue in the controller itself. The transmission isn't going to be very hot in that time period but if there is a bad component in the controller it could get hot enough to shut down. Easy test would be to run it around until the system trips. Pull into a car wash and use the wand to spray the transmission and cooler down. If the issue is transmission heat the cooling should make it return to normal in a couple minutes rather than an hour.

Hello guys, thank you for the prompt and descriptive advise.

Yacine,
I actually had the vehicle taken to the Porsche dealership, and after long and persuasive negotiations they decided to replace “Sensor Pack (Position Sensor with Speed and Temperature Sensors)
- Part#: 97031708500”.
Actually it seemed they never done this job before, so they even asked for the part number, and offered no guarantees...
In their opinion solution was the infamous replacement of the PDK gearbox for $35K, ... YES! Thirty Five Thousand US Dollars. * Of course, I’ve started laughing, because I could not do anything else to calm my anger....
Finally they supposed replaced the sensor pack, but the issue is still present.
I even provided them with Service Bulletins from the NHTSA web site

https://rennlist.com/forums/attachments/997-forum/1233417d1501772137-porsche-technical-bulletin-for-2009-2011-pdk-cars-sb-10052517-4176.pdf

But $2165 later my vehicle is still not running properly.

Steve W,
Thank you for your advice, I’ll try to apply your proposal.

Ken,

Yes sir, the part was directly from the dealership paid over $900.

Guys,
I just don’t know who to fight next. The dealership’s incompetence, or the manufacturer for selling a $87,000 vehicle that 82K miles later supposedly requires a $35K new transmission.

I could use more ideas if there are any.

Thanks

I would find an independent shop and have them look at it. The trick with Porsche is having the correct scan tool and a quality person who knows how to use it for more than a paperweight...

Dear Steve and all. Thank you for all of your input. I have a 2010 Panamera 4s with 37 K Kilometers. As I was cruising down the highway I switched to Sports mode and got the "Fault Transmission" , "Check Engine" appeared on the dash. The car would not shift out of 2nd gear and had it towed to the dealership. It's been there for over 2-weeks and they are saying that they will start by replacing the pressure sensor of the transmission. If that does not work they will replace the gear box casing, and if that does not work then they will replace the gear box. I am out of warranty and extremely frustrated. Please advise if I should proceed in replacing the pressure sensor. Thanks for your feedback.

Do you know what the codes that were stored are? The lights indicate that there are codes stored. That would give an idea of what the computer thinks is wrong.

Here is a guide to help you get the codes:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Please run down this guide and report back.

Dear Steve and Ken thank you for getting back to me, it is highly appreciated. The car is currently at the dealership and I do not have the error reading tool. I will contact the dealership next Sunday and try to get the error codes which I will share at that time and will be deeply grateful for your support.

Thanks. we would like to see what's going on to help get the car fixed.

Dear Steve and Ken,
Thanks for your support. I have attached the error codes as sent to me through the Porsche Dealership. I went ahead and ordered a new pressure sensor that should arrive today. I look forward to your feedback. Thanks again.

With those codes it could be the sensor giving a bad reading easy enough. Testing is to see if the wiring is shorted to ground or if it's open. If neither of those is the issue then it is most likely the sensor.

Thank you Steve. I will replace the sensor tomorrow and will let you know if that resolved the problem.

Hi Steve. The dealership have replaced the pressure sensor and have tested it for 65 kilometers. So far the error did not reappear. I am cautiously optimistic that the problem has been resolved. Thanks again for yours and Ken's support you guided me to be on the right track. Much appreciated.

Good to hear. The test for that sensor runs when you turn on the key and is a continuous monitor with the engine running. I would say it should be fixed if it didn't set the code really quick.

Hi Steve. Thanks for that pointer. It has not shown the error and so far so good. However the dealership asked me to drive the car for about 1,000 kilometers to make sure that the problem is fixed. After that they asked me to come back in to replace the transmission oil.

Let us know what happens in 1,000 miles, we would like to know as well.

Hi Ken, the car is running smooth after 1,000 KM's again thank you all for all the support.

Great to hear. Thank you for using 2CarPros. Please return anytime with your automotive questions.

Hello guys,

I need your help please.
I am really tired from this car / Porsche Carrera s 2009 ( 997 )

I have the fault P1731,P1732,P1733 and P1734.
I replaced the pdk control unit brand new.
The distance sensors.
And I tried also to replace the full transmission from another car which is was working fine but nothing was useful!
I made test for the signals from the pdk and the gear .
And from the pdk control to the engine control unit and everything is fine.
I don’t know what I have to do. please help me.

The u4018 code concerns me. lets do a CAN scan to see what comes up. Here is a video to show you how:

https://youtu.be/InIlnsjOVFA

Please run down this guide and report back.