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Sir, you might want to contact Amet here... I'm pretty sure he replaced pressure sensors on his 911.
Oh yes, your client is in for a surprise
Appreciate it, I definitely will! Saw his input on Damien's post, but was unaware he had done the sensors also.
And I'm sure I'll be speaking with you guys soon also, especially after not being able to repair two other client's distance sensor issues previously while not wanting to trust used Chinese parts.
Glad you're taking the initiative with the sensor packs!
Try to get clarification from the dealer exactly what the fault codes are and the exact wording of the fault (a print out if you can). The PDK uses both a "transmission control unit" (the TCU, a small $800 computer in the car) and an "electrohydraulic control unit" (aka the valve body, $1700 and inside the transmission). I think it's the former but you need to clarify for certain. If so it's not a big problem as they can replace the TCU, recalibrate the transmission, and you should be on your way. If it's the latter it's a pan drop to replace but it's still not a transmission R&R. Either way it's not too bad. Both are not difficult to DIY but you'll need a PIWIS to cal the transmission.
Cut and paste from my 981 thread Update I have a new sensor on the way from T-Design. They were easy to work with and offered some good advice. I found several shops that said they could do the work but they had only worked on Panamera's before. I don't think they knew the difference between the two types of transmissions. I did not have a good feeling about them. A friend in the racing community in Atlanta recommended a shop in Charleston SC. I spoke with them this morning and feel confident they can help me. Here's a link. I pick the car up Monday morning for the trip home then on to Charleston next week.
Cut and paste from my 981 thread Update I have a new sensor on the way from T-Design. They were easy to work with and offered some good advice. I found several shops that said they could do the work but they had only worked on Panamera's before. I don't think they knew the difference between the two types of transmissions. I did not have a good feeling about them. A friend in the racing community in Atlanta recommended a shop in Charleston SC. I spoke with them this morning and feel confident they can help me. Here's a link. I pick the car up Monday morning for the trip home then on to Charleston next week.
edit Just got off the phone with another shop. It's in VA Beach. I will be dropping the car off there Monday morning. https://www.lmnmotorsports.com/
Can you elaborate on your fault code? Your original post talked about a "control unit" which isn't the same as the T-design unit. Not saying the T-design unit isn't needed, just trying to understand the fault better so we can learn from it.
Hey Ptech, thanks for the compliment. I've long appreciated your contributions here and have found they are right on the money. There's no substitute for experience.
Regarding the sensor I wish I could be more help but you are right regarding the ambiguity of 991.1 applicability. The part number I listed (9G1.307.385.05) shows up on the 997.2/987.2 PDK parts lists but the location isn't shown. That's how I was able to figure out it's the clutch fluid sensor as it's not used anywhere else in the 997/987 PDK. Take a look at this link from Atlanta Perimeter:
If you click on "what this fits" you'll see only 997/987 model years with the exception of the GT3 that says 2014-2015. Pretty strange as I don't see why it would have a Gen1 PDK.
Now if you search on a 991.1 PDK (used 2014 Carrera as an example) you'll find the same pressure sensor PN listed (9G1.307.385.05):
It's listed as item #30 and here it is shown on the diagram but only as gear oil pressure sensor located on the outside of the transmission see the graphic below). The 997/987 PDK doesn't have this sensor.
I don't know for sure but I strongly suspect it's the same sensor used on the clutch fluid (997/987 and 991/981) and the gear oil (991/981 only). I don't have a 991 Katolog but if anyone does it would be interesting to see the quantity listed.
We do know for sure that the ZF OEM number (0501 326 481) is correct for the 997/987 as it's printed right on the part and it's been eyeballed. It's also cheaper to buy this part rather than the Porsche PN.
So the bottom line is that we don't know for certain it's the same sensor on the 991 but a lot of circumstantial evidence suggests it probably is. Good luck and please let us know how it goes.
Sorry, I missed your response earlier! So after some digging and confirming what I saw (and didn't see) yesterday, I believe their PET link is wrong for a 991 based on what I see for #30 on my end.
It only shows as a temperature sensor, PN 991 606 391 00, without the secondary option for a pressure sensor as with their link. I also just confirmed that the second option for "pressure sensor" doesn't exist with my dealer contact in their PET.
I was waiting to see if a damaged PDK was actually going to be called back as a core with one of my dealership guys in order to dissect it to verify, but just got word that it is indeed back in a crate for shipment. I do however have a 991.1 GT3 here currently so I will see what it has externally as I don't remember seeing a temp sensor, but also may not have been looking closely enough at them in the past. It's definitely not an early PDK version, and is actually a PDK-S by all accounts. I will report back with what I find.
If all else fails, I'll have the car in question shipped to me as the customer wishes to do so, and is aware he may be somewhat of a Guinea pig in order to attempt pressure sensor replacements if that is indeed the issue on the 991 also as we suspect.
I would contact Blue Chips in Denver, they have one of the best Porsche techs locally, who also recently left dealership life to join them. They may be interested based on the clientele they see for future PDK repairs.
I called Blue Chip, but they didn't feel comfortable with opening up the PDK.
Did they look at what it takes? Or the tech who left dealership is too used to corporate mantra "PDK is sacred"
Nothing more than just dialogue correspondence over text; I reported the code that I pulled, surmised my thoughts as to what I suspect it might be, and asked if this was something that they felt was within their scope of capabilities. They just didn't feel that it was something they felt comfortable with attempting to perform.
Sorry, I missed your response earlier! So after some digging and confirming what I saw (and didn't see) yesterday, I believe their PET link is wrong for a 991 based on what I see for #30 on my end.
It only shows as a temperature sensor, PN 991 606 391 00, without the secondary option for a pressure sensor as with their link. I also just confirmed that the second option for "pressure sensor" doesn't exist with my dealer contact in their PET.
...
I was waiting to see if a damaged PDK was actually going to be called back as a core with one of my dealership guys in order to dissect it to verify, but just got word that it is indeed back in a crate for shipment. I do however have a 991.1 GT3 here currently so I will see what it has externally as I don't remember seeing a temp sensor, but also may not have been looking closely enough at them in the past. It's definitely not an early PDK version, and is actually a PDK-S by all accounts. I will report back with what I find.
If all else fails, I'll have the car in question shipped to me as the customer wishes to do so, and is aware he may be somewhat of a Guinea pig in order to attempt pressure sensor replacements if that is indeed the issue on the 991 also as we suspect.
Looking forward to what you find as I think you are right in that the Atlanta Perimeter PET is confusing the gear oil temp and pressure sensors since they are both listed as item 30. The drawing of item 30 also looks the wrong size to be the pressure sensor.
I did find this interesting picture on a Polish website when googling the 9G1.307.385.05 part number.
Note that items 1 and 3 on the right photo are obviously the clutch pressure sensors. Item #2 is the actual location of the third pressure sensor added to the 991. It may only apply to locking differential models. The website claims it's for "2009 Gen 2" which I assume means the 997.2 and 987.2. But neither of those cars have the third pressure sensor and I have never seen one in this location on the 997/987 cars.
My suspicion is that Porsche never intended these to be replaced by dealers or DIY'ers since they are hidden behind the clutch. If you follow the 997 PDK flow diagram for a pressure sensor fault there is never a step to replace the pressure sensor but ends at the infamous "contact the importer". I think they mistakenly included it in the 997.2 PET and then fixed that by removing it from the 991 PET. I don't see any reason why they wouldn't have continued using these in the 991/981 as they used it in the Panamera up to 2016.
Just had another thought as I realized that Atlanta Perimeter link including the pressure sensor was actually for the 991 GT3 PDK. They also listed the 2014-2015 GT3 as an applicable vehicle for the pressure sensor but not the other 991's. Could it be that if you shell out for a GT3 you get the right to replace some parts in the PDK unlike us peon Carrera and Turbo owners? In other words, it's the exact same part but they only tell you what they are in the GT3 PET. It wouldn't surprise me.
I have just finished opening/closing my 991.1 transmission.
Clutch pressure sensors can be tested using piwis or any autel diagnostic reader, both clutch sensors should be the same value (one of mine was 0.9bar while other was 1.3) and that seems to be an issue with 2nd to 1st gear clunky shift.
once opened, I have tested the sensor by applying 5v to the outer pins and measured the center pin. Failing sensor gave me 0.49v while good one was 0.54v, replacement sensors were all 0.54v. We had sensors laying around from few transmissions that were used for parts so we didn’t have to buy them, but I can confirm that the numbers are the same as mentioned previously.
interestingly enough, car did not report the lower value as an error, it just pushed more pressure to compensate for it and I think that’s why my downshifts were rough.
my 991.1 has 3 sensors, didn’t look too close why that is… below are some photos of the job, 3rd sensor is top right, next to the oil pump gear and behind the oil metal pipe
I have just finished opening/closing my 991.1 transmission.
Clutch pressure sensors can be tested using piwis or any autel diagnostic reader, both clutch sensors should be the same value (one of mine was 0.9bar while other was 1.3) and that seems to be an issue with 2nd to 1st gear clunky shift.
once opened, I have tested the sensor by applying 5v to the outer pins and measured the center pin. Failing sensor gave me 0.49v while good one was 0.54v, replacement sensors were all 0.54v. We had sensors laying around from few transmissions that were used for parts so we didn’t have to buy them, but I can confirm that the numbers are the same as mentioned previously.
interestingly enough, car did not report the lower value as an error, it just pushed more pressure to compensate for it and I think that’s why my downshifts were rough.
my 991.1 has 3 sensors, didn’t look too close why that is… below are some photos of the job, 3rd sensor is top right, next to the oil pump gear and behind the oil metal pipe
Thanks amet, great work and great photos. That confirms my theory that they are the same part as in the 997/987 but Porsche left them out of the 991 PET for some reason (and probably the 981 PET). They are listed for my 997.2 Turbo. They really aren't going to make this easy for us. Since the same part is a replaceable item on the Panamera, Porsche should continue to make them available.
Hopefully that fixes it for you. If not you probably want to take a look at solenoids EDS1 and EDS2.
Thanks amet, great work and great photos. That confirms my theory that they are the same part as in the 997/987 but Porsche left them out of the 991 PET for some reason (and probably the 981 PET). They are listed for my 997.2 Turbo. They really aren't going to make this easy for us. Since the same part is a replaceable item on the Panamera, Porsche should continue to make them available.
Hopefully that fixes it for you. If not you probably want to take a look at solenoids EDS1 and EDS2.
it seems fixed, I have replaced all solenoids as well just to be on a safe side. Didn't want to open it again
Ok mystery solved. I knew I had read about that third pressure sensor someplace but couldn't remember where, it's in the 991 Tecknik. It's for the locking differential and works with the additional solenoid (EDS7) added at the bottom of the bell housing. There's also an added pipe next to the third sensor (seen in amet's photo) that isn't in the 997/987's. So this extra stuff should only be present in 991/981 PDKs with the locking diff option.
I'm going to edit my references to a gear oil pressure sensor above to not mislead people as I think it uses clutch (hydraulic) fluid.
I have just finished opening/closing my 991.1 transmission.
Clutch pressure sensors can be tested using piwis or any autel diagnostic reader, both clutch sensors should be the same value (one of mine was 0.9bar while other was 1.3) and that seems to be an issue with 2nd to 1st gear clunky shift.
once opened, I have tested the sensor by applying 5v to the outer pins and measured the center pin. Failing sensor gave me 0.49v while good one was 0.54v, replacement sensors were all 0.54v. We had sensors laying around from few transmissions that were used for parts so we didn’t have to buy them, but I can confirm that the numbers are the same as mentioned previously.
interestingly enough, car did not report the lower value as an error, it just pushed more pressure to compensate for it and I think that’s why my downshifts were rough.
my 991.1 has 3 sensors, didn’t look too close why that is… below are some photos of the job, 3rd sensor is top right, next to the oil pump gear and behind the oil metal pipe
Amet, you are a life saver! That info changes things entirely, and means saving this and future client's PDK's from unnecessary and costly replacements.
I've been in several situations previously where a decision was typically made to simply get out of the car, at a severe loss, rather than spend the $15-20k just to have the same exact vehicle they had prior to a failure occurring out of nowhere.
With your information, I can now confidently tell this client that there is a high probability that we can save his 991 transmission, which is a much better feeling than making the dreaded phone call in the past, or attempting TCM replacements on a hope and a prayer. So thank you to you, PV997 and everyone else who's taken the path unknown to answer these questions.
On a side note, since we now have the answer, I did inspect both a 991.1 GT3 and a 981 Cayman here in order to confirm what sensor was listed for #30, and they both appear to be the typical smaller temperature sensor. They are in slightly different locations, but they are indeed the same PN and physical sensor. I couldn't remember seeing a larger pressure sensor externally, so I wanted to confirm either way.
not sure if the temperature sensor is any different, on my car it looked really small... yours on 991 might just be an upgraded version (mine is 2012.5)
on a separate note, @PV997 you can see the EDS7 solenoid in the photo below, as well as the temperature sensor... hope it helps.
07-15-2021, 01:43 PM
