mujeriega

Looks like Bronz is selling his broken PDK for $1k if anyone is willing to tear down and learn the PDF in person. Seems like fixing this thing would bring a hefty profit too if it's just sensors.

Chris McSparron

Backstory: car has 79k miles, tracked 10 times a year, PDK clutch/gear oil changed with Driven fluids before and after track season. Car has been flawless, finished up a track weekend at Chuckwalla and a week later after daily driving it to work, my wife goes to start the car in the morning and display shows "Trans fault poss. No R gear. Drive on pos"

I had forward gears 1,3,5,7 so I drove to local Porsche race shop. They found 4 trans codes in TCM, but because most of their race cars are MT, they didn't want to proceed. They cleared codes and then there were no forward gears. Towed car to another shop recommend to me by LN Engineering and their diagnosis is as follows:

Transmission is showing codes. Car had 1, 3, 5 and 7 gears and codes were cleared. Now the car won't go into gear.

- Transmission codes.
- 4 codes PDK
- No Reverse Drive at first
- Had 1, 3, 5, 7 gears and was cleared by Vision Motorsports and now has none.
- Has a computer tune for the engine.
- Changed fluids with Driven before and after track events.
- Front trunk does not pop
Notes:
Checked with autologic but could not pull factory codes
Connected battery charger
Checked with piwis found following codes:
P1764 (synchronization, engagement block or gear skip)
P1765 (gear disengagement lock)
Current P1774 (gear valve two, hydraulic fault)
Current P1731 (displ. Sensor shift rod gears 4/6, implausible signal)
Current P1735 (distance sensor f. Shift rod 4/6-short term fault)

Followed fault finder for code P1774
It asked if fluid for clutch was full
checked clutch fluid found low
Performed filling procedure filled 1.0 qt
Cleared codes and checked operation found still inop
Initially no codes set took about 3 min of running to set fault code
Checked codes found
P1764 synchronization, engagement block or gear skip

Next morning rechecked fluid found good.
Checked codes found
P1731
P1735
P1764
Current P1870
Cleared and rechecked
Unable to clear
Checked fault findings on current code P1870
Says to calibrate shift rods

Performed calibration as piwis instructs
Unable to perform calibration due to fault codes not able to clear
Performed handover and checked transmission for operation. Found no trans operation but Code
P1764

Attempted calibration again
Will not calibrate with fault code present. Could not clear faults
Checked flow charts
Inspected wiring harness for damage
Harness has no signs of chafing or damage

Attempted another handover to clear faults
Faults still present
Unable to perform calibration
Performed hard reset on control unit
Tried to clear codes
Cleared codes After hand over
Performed a vehicle log and was able to perform calibration
Unable to perform calibration- calibration failed during shift rod calibration (see picture)

Fault code
Current P1870
P1735

No matter how many times I get code P1870 to clear it will return.
Fault description of P1870 is “Data record for calibration of shift rods is not valid“
Remedy For fault is calibration

Unable to perform calibration found calibration failed “cancellation conditions: not all column can be reached with max force”

As per porsche document fault code coded a control unit from another vehicle to see if module was bad or transmission had fault.
Performed coding on a module and found
P174B- PDK control unit, interchange detected
P1765- Gear disengagement lock

As per fault code break down for P1765 asks to replace Hydraulic switching unit.

Due to erratic codes and complaint, suggest replacement of PDK trans and control unit.

After reading this thread, I feel compelled to call Porsche's bluff (according to Piwis diagnosis)by not replacing PDK and TCM, but instead replace hydraulic valve body and recalibrate the TCM. The shop purchased another Trans control module to try on my car as per Piwis instructions, and determined hydraulic failure, so if my TCM is fried they have a new one to try with a new hydraulic valve body

My logic is that due to the Piwis procedure screenshots above, it's clear that with either a malfunctioning hydraulic valve body and/or TCM, the calibration of the shift rods was unable to be performed..... no $hit! So the shops, and Porsche's solution is to replace everything . Bravo!
What kills me is that the trans pan wasn't even dropped to visually inspect for anything like metal shavings so how can it be concluded that there is any mechanical failure?
See the Porsche circular logic here? The calibration cant be performed because of malfunctioning hydraulic valve body so let's just replace the whole PDK because we're too lazy or scared to touch the insides of the transmission. Ironically, I had a B8 S4 with a similar ZF dual clutch that had a mechatronics failure, which was a widely known issue, simple fix was to replace valve body, clear codes, calibrate, then drive away happy. Will this PDK play ball?


If a new hydraulic valve body is installed and calibrated it should solve the problem. Or am I wrong?

PV997

Hi Chris - Sorry for the delay in commenting as I've been away from Rennlist for a while. From your symptoms I think it likely is the valve body based on what I learned in writing this post. The 1-3-5-7 pattern seems like it could be one of the clutch solenoids specifically, a $50 part (discussed in the valve body section of the post). I'll go through the your comment in detail over the next few days and let you know if anything pops out.

Please let us know if there are any updates. BTW, I'm also in So Cal so let me know if I can help.

jrodporsche

PV997, wow what a great document you wrote about the PDK and how it works. I am not a mechanic but I love the attention to detail you put into your research. With your knowledge, Im writing to you to see if you can point me in the right direction with an issue I have with my 2014 911 turbo, 28k miles.
I have a 2014 991 turbo. I have a small rattle sound inside the cabin at idle. At first we thought the noise may be coming from the rear engine pully tentioner, but you can only hear the rattle inside the cabin. It is hard to describe the noise , it come and goes and its not very loud, but you can hear it if you try to notice. it is like a rotating disk metal rubbing, swooshing sound. Goes in and out.. I think when car is cold it sounds more.. . It happens with no, or very little load on the pdk. If you accelerate at idle, the noise seams to decrease while driving your really can not. hear it. It can mostly be heard at idle ( low RPM), stopped at a traffic light etc. On a scale of 10 being very loud, its at about a 1 - 2 while at idle.
A local porsche shop said the noise is coming from the pdk clutch plates, maybe loose tolerance and slapping against each other undo low load. He got under the car with a listening device and said rattle noise is coming from the PDK area. More towards the front of the car under driver seat area.
He changed the PDK oil and noise is still there at idle. Car runs and shifts fine.
What do you think may be causing this swishing noise in the PDK.
Have you heard of this before on 991 model cars?
Should I be worried about this?
thank you in advance for your time to answer.
Regard.... John

PV997

Hey John - Thanks for the kind words. If it's in the clutch then there isn't too much you can do unfortunately as it's a sealed unit and replacements aren't readily available. There is a Chinese aftermarket website that advertises remanufactured clutches (linked in the clutch section of the post) but I don't know anything about their reliability or availability.

The clutch assembly is sealed from the factory and the metal case literally has to be machined open to access the plates. It's meant to last a lifetime and supposedly is rated for 200k miles. Its a wet clutch and there is no way to make adjustments to the clutch itself unfortunately. Here's a Jay Leno's Garage episode where they open one up to see inside (go to 4:15 for the clutch section):


You can see the interleaved friction plates of the two clutches in the video. The only thing I can think of is that there could be an issue with the fluid pressure in the clutch, this pressure is regulated by two solenoids in the valve body. There are two clutches each with it's own fluid circuit, clutch 1 is for R-1-3-5-7 and clutch 2 is for 2-4-6. So if the sound is present in first gear but not second gear this could be a clue. The clutch fluid pressure sensors can be read with a PIWIS (or a clone), along with the solenoid status for the clutch pressure control. If you ask a dealership to do this they will probably give you a blank look but an adventurous indy could check it for you. Good luck and please post if you find anything.

jrodporsche

Do you think the PDK clutch reset can make a difference with this sound?

PV997

I've not heard of a PDK clutch reset, just a general PDK reset. I'm pretty sure the PDK reset clears the memory that is used in adapting the PDK responsiveness to your driving style. By resetting it you are starting over from scratch. I really don't see how it could help but there's no harm in trying since it's free.

Something more likely to help is the PDK torque adaptation calibration. This process is initiated with the PIWIS and then the tech drives the car over a range of speeds with a minimum of thirty shifts. New calibration values are calculated by comparing the PDK sensor values with various inputs from the ECU. If you want to read how it's done see the first linked document at the bottom of the post, go to page 14, starting at section 3.6. This could possibly fix the clutch pressure if there is an issue, but that's pure speculation on my part. If you know someone with a PIWIS clone they can run it. I've heard the dealer charges $325 and there is no guarantee it will fix it so please don't spend the money based on what I say alone.

PV997

Hi Alexey - Glad you were able to get it back together and thanks for posting the photo. The ZF part number is the bottom row on numbers (0501-326-481) and it's the same PN I have in the post. Thanks for confirming it for us.

Mrhobbiest

Thanks for sharing your hard work and extensive info. I'm just starting this journey into the PDK rabbit hole. Story to follow as time allows. Presently, 997.2 sitting at dealership in limp-home mode.

PV997

Please let us know how it goes and make sure you get all stored fault codes documented before they clear them. Lots of things can cause limp home mode, even something as simple as failing temp sensor. The transmission control unit shuts off all sorts of PDK functions even with simple failures, the symptoms from this often make the problem look much worse than it is.

Darklockz

hi, all..

first.. thank you for this page! and sorry for my broken english i do my best

Ok, here's my problem, panamera turbo 2012... one day, cold start, no reverse
let the car get up to temp, no reverse still.. stop the engine, re-start.. i can now reverse
tried to run around the block, no problem at all everything seems fine.. so i call porsche rivesud
i ask them to check trans oil level.. the tech gets mad tell me they wont do it but for 400$ they will diag the car 2 hours
i accept.. but before i cleared the codes and try the car again.. no problem at all
2 days later i drive the car to the dealer (code didnt show up since, and the car shift like it should)
the next morning i receive the call from porsche rivesud, 4000$ bill "theres something physically broken inside the trans" they say
i've never seen a internally broken trans engaging as the oil gets hot, so im very sceptical about it.. decided to take the car back like that
when i came to pay the diag and talk with them.. they told me previous owner probably didnt change the oil and thats it, but refuse to even look at it
for now, i didnt read the tech paper and didnt know they NEVER could reproduce the problem while the car was at the dealer ( 2 day )
the car had p1731 and p1732 stored so they could see it but couldnt reproduce the problem at all.. the tech did check the value and say everything was normal.
he says " i suggest starting with the replacement of the sensors" the sensor they want to change is the temperature sensor
So, i take the car back to my house ( about 30 min from the dealer ) with no problem at all. drive the car for 3 days and then one day after an hour it get stock on the 7th gear
manage to slowly get on the side of the road, ignition off, ingnition on.. i get 2nd gear and park the car and leave it at the gas station for an hour or 2..
came back, 0 problem at all car drive to the house without a single problem again.. codes are always the same p1731, p1732, p0700

the car will drive ok for X amount of time, and then suddenly stick to one gear till i stop the car and then refuse to engage whatever the gear or the gear selection
sometime it will do it on a cold start too.. the only way ive found to be able to make it engage again is wait time.. like it reset itself

I was very frustrated at porsche dealer to "change whatever" for "whatever reason" without testing anything.. like pay and we'll see how it goes..
Im not that type of guy, and my logic cant handle this kind of thing... so i walked away and found this page!


now im trying to find information on how to get to the tcu... cant find anything on 970.. anyone have info on this?

thanks in advance!

PV997

Hey Darklockz - First thing I should point out is that the Panamera PDK is different from that used in the 997/987 so not everything in the main post directly applies to your transmission. That being said there are many similarities.

The P1731 and P1732 are faults with the distance sensors that measure displacement of the shift rods (these sensors are discussed in the main post). This fault means they are measuring outside of the normal range of 10% to 90%. A short or open circuit in these sensors or the harnesses to them could cause this. P0700 isn't listed in the fault list I have so I'm not sure what that one is. There are other P070x codes (but not P0700) that generally refer to a fault in the self test the control unit runs when powered up.

The good news is that the distance sensor in the Panamera PDK is available from Porsche and replaceable without dropping the transmission (unlike the 997/987). I've posted a photo of it below, it's accessible by dropping the PDK oil pan. This part costs $500 so I would perform diagnostic tests prior to replacing it. Like I mentioned above, my main post was directed at the 997/987 so I don't know the specifics of the 970 PDK. There are several posts out there on failure of this part on the 970, so you should be able to find more info googling it. Good luck.



UPDATE: Added a drawing showing the location of the distance (displacement) sensor in the Panamera PDK, it's item 21 below.

Darklockz

thank you

yeah i understand they are different
also, thats the same part i get when i put the part number the dealer was about to change in google so..
well they want 4197,55$ for the job and.. all the advisor was able to tell me its "something physically broken inside"
"probably do to the original owner not changing oil" and then i read the tech note and understand they couldnt reproduce the fault
he wrote "there's no check engine light when i tested it, p1731 and p1732 was stored he did look at actual values and everything was fine
suggest starting with replacing sensor" (sry he wrote that in french so thats my broken english again lol)

Im sure if i had talked to the tech instead of that advisor (she was very.. unpleasant to speak with like she just dont care)
i would have had enough trust to go ahead and make them repair the car. anyway thank you for your reply

Mrhobbiest

*Warning, sorry it's a long story - and the saga continues.
PDK Transmission

2010 Porsche 911 Carrera S 997.2

Not a daily driver.

Transmission problems started on the track March 2019. Odometer just reached 60k miles.

My last run of the day at CMP leaving turn eight full power heading towards nine the dash flashed a transmission code, “Transmission emergency run”. I pitted and returned to the paddock, shut off the car. After some time to cool I restarted the car and put into gear and the car shifted normally. Then started my couple hour journey home with the check engine light on but there was no transmission error messages on the cluster and the car operated normally. I stopped twice on the way home once for fuel another just to cool the car.



Next day drove to indy shop (normal shifting) to retrieve codes:

Check engine light was still on

U0155 communication instrument cluster control unit

U0146 communication Gateway control unit

U0418 Fault, PSM control unit

Transmission PDK

P17F1 dual-clutch transmission, over temperature

P17F0 dual-clutch transmission, over temperature

5400 Sport mode fault

C152 communication psm control unit (drive)

C150 control unit communication, engine electronics drive

8012 power supply, above lower limit value

8023 outside air recirculation flap motor




After lengthy discussion decided to clear codes and headed to dealership a couple days later for scheduled dual-clutch fluid change.

Drove an hour to the dealership, normal shift operation, no warning lights or codes returned. After the service was performed I drove out of parking lot and cluster panel lit up with transmission overheat warning, CEL, and limp home mode. So I went straight back to service department, stuck in 2nd gear. They kept the car for several days and could not figure out the problem. Note from dealership: “The technician has scanned the faults so far and a few had come up.

P0730 - Transmission ratio monitoring;

P17F0 - Transmission overtemperature, stage 1 (exceeds limit value);

U0418 - CAN fault, brake;

5400 - Sport mode fault.

On Monday, our shop foreman will be looking into this further to get things right.”

The dealership checked everything again and told me a week later it was corrected, come and pick-up your car. Once I drove the car out of the parking lot the cluster lit up again with same warnings so I drove right back to service department in “limp to dealership” mode. Well, the foreman was unable to diagnose or solve the problems.

They spent the next week in discussion with PCNA and decided the best course of action was new transmission = $32k. No thanks, I'll get second opinion. I picked up the car and drove it about an hour before the codes returned and finished my drive stuck in 4th or 5th gear(sorry I can't remember). Codes present:

P17F0

P17F1

P17F2

5400

Several days later cleared codes and drove a hour and a half (without issues) to another dealership for diagnoses and treatment. They were unable to reproduce the problems. I was told, the tech did hooked up the computer and cycled all the valves and “re-booted” the transmission system. A few days later I drove the car (Hour and half) home without issue. April 2019

Drove the car through the hot summer road trips and PCA events. No issues.

Round trip to/fro and track day in Oct at VIR. No issues.

Drove sparingly in the winter months but still, No issues.

March 2020, track event day 2 while paddock cool-down lap, warning light and no reverse gear. Generic code reader: P0730 Incorrect Gear Ratio

Cleared code, cooled and was able to run a couple more sessions and travel home with no issues.

In and out of my garage a couple times for a wash and quick local drives. Two weeks later heading out for a local drive, 3 miles from the house stuck in 5th or 6th gear with over temperature transmission warning light on the cluster panel. Generic code: P0730 Incorrect Gear Ratio. Restart car travel and couple miles CEL comes on and puts car into limp home mode 2nd gear.

To make a long story even longer, a third dealership wanted a chance to earn my business by solving the problem. Their solution, $22k new transmission. I have not seen the stored codes from the latest diagnoses as of yet but I will edit this saga when info is available. I assume the codes will be the same. Looks like I'm going to have to crack this thing open. HELP!

PV997

Hey Mrhobbiest - As you noted P17F0, P17F1, and P17F2 are all over temp faults from the PDK. The 997 PDK has a single temperature sensor located in the clutch fluid section directly above the valve body. Here's the description of the P17F0 fault, the others are identical.



This makes me suspicious that it could be a bad temp sensor, particularly since this was a known problem with the 997 PDKs. Note the fault effects, these are things that the TCU does in response to the fault. The main post has a section on this sensor (including how to measure resistance values) and the second PDF document linked at the bottom of the post has details on repairing it.

P0730 is a weird fault as it indicates a mismatch between what speed the ECU thinks the engine is turning versus that of what the PDK speed sensor is measuring inside the transmission. Here is the fault.




On first blush this looks unrelated to the temp sensor. Seems to me this is one of four things:

• The PDK speed sensor or its harness has an issue
• There is problem with the PDK clutch (slipping) so there actually is a speed mismatch
• The TCU is receiving bad info from the ECU regarding the engine speed
• The TCU has an issue (corrupt software, hardware failure on sensor inputs, etc.)

The fact that the temp sensor and gear ratio faults come on together is something that I would focus on. They are two completely different sensors on different harnesses (come off different connectors on the PDK) so it seems unlikely that both sensors are failing at the same time. If the clutch fluid truly was overheating I suppose it could make the clutch slip (particularly if the fluid was burned from prior episodes) so that might make sense. Alternatively, it could be an issue with the TCU ($700 vs $15K for a transmission) in that it's not reading the sensors correctly.

If you have access to a PIWIS clone you can read these sensors in real time and create datalogs. It would be good to know if the temp sensor is gradually going up to a high value as opposed to the sensors suddenly going haywire. This would be helpful to know if there is a real mechanical malfunction or just the TCU reacting to bad sensor data. The dealer can measure this with their PIWIS but since it isn't called out in their "check the box" flow diagrams I think it's very unlikely they would do it.

A couple of other thoughts; there is some evidence of the gear oil overheating when tracking 997/987 PDKs (see the discussion with Hatzenbach starting at comment #66). There isn't a gear oil temp sensor but if it gets hot enough it could make the clutch fluid overheat. In the 991/981s Porsche added a gear oil cooler to the PDK, something they weren't planning on doing originally according to the 2008 ZF whitepaper on the transmission. Also do you have the third radiator?

Hopefully this is helpful, I'll post if I come up with anything else.