Originally Posted by PV997

Hi Phasenfus - Your error codes are identical to those Mr Hobbiest saw on his 997, I would highly recommend you read his comments and our responses.

The transmission ratio fault means that the TCU thinks one of the clutches is slipping. The ratio it refers to is that of the engine speed vs. the speed sensor in the transmission after the clutch, i.e. they don't match each other. So either there actually is a problem with the clutch causing slipping (you should be able to tell this) or there is a problem with the sensor data. Take a look at comment #176 where Mr. Hobbiest posted some of the data he captured. The first file shows the speed sensor (top plot) and you can see how erratic it is. The TCU is comparing this to the engine speed and throwing a fault because they don't match.

Mr. Hobbiest did a great job measuring his fluid temperature when his transmission faulted as being over temp. The fluid temperature was fine. Take a look at comment #81 where there is an excerpt from the 997 Technik training material. It says the temp is measured but it is also calculated based on how much the TCU thinks the transmission is slipping. We know from the P0730 ratio fault that the TCU thinks the clutch is slipping so it's very likely the temp faults were thrown by the calculated temp model.

So was your car showing any signs of clutch slippage? If so it could be a problem with the clutch itself or the solenoids controlling fluid pressure to it. If not, it very well could be an issue with the speed sensor and the TCU thinks there's a problem when there really isn't. Quite a coincidence that what you are seeing seems to match what Mr. Hobbiest is seeing.

Originally Posted by 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?

Originally Posted by 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.

Originally Posted by Mrhobbiest

Up under the car yesterday to check the trans connection. No signs of trouble here. Don't like the wire crimp and twist and will have to check.

Tight twist back toward the TCU.

Anyone know which wire color is for the Speed Sensor 1?

Originally Posted by Chris McSparron

I got the car back from Callace Rennsport in Torrance. Highly recommend anyone in the SoCal area consider them. They have over 30 years experience and the owner ran the Porsche Le Mans team at one point. After the above diagnostics and the owner talking to Porsche about my car it was concluded the clutch packs were worn and the debris found it's way into the solenoids and valves causing malfunctioning. Both Porsche and LN Engineering said that Replacing the valve body will not fix the problem as the clutch pack debris will recur and damage the new valve body. Porsche said that since my car has been tracked and has 80k miles this is what is to be expected. A remanufactured PDK unit was ordered from Stuttgart in Porsche's super-secret factory. Porsche will warranty the unit for one year/12,000 miles. It was $11,700 with a core swap.....ouch!! A new transmission control module was also purchased as LN told me they run into issues re-using the TCM from the damaged transmission. There's another $1500. Also the vacuum/oil pump was leaking and replaced as that is another failure point for cars that see track time. The two pre-formed hard coolant lines were both leaking at the seals which may be something for others to monitor as they put more miles and track time on their cars.

I will say this, after driving with a new trans, you can tell the clutch packs feel very tight and precise, whereas before with worn clutch packs the shifting and feel was noticeably different. I guess that serves as an indicator for others to follow.

If anything, my car serves as a good example of what to expect as you accumulate miles and track time. I bought the car two years ago with 40k on the clock, I have only tracked it 15 times and the rest of the miles were put on by my wife as a daily driver. It currently has 80,200 miles

It is what it is. Ironically I was just about to put the car up for sale before this happened. I am still going to sell it, with a brand new trans under warranty and a laundry list of services and parts it should be a good value to someone.

Originally Posted by PV997

Hey Chris - Thanks for following up and I agree with you about Callas, they are in my neighborhood and are top notch. It's completely anecdotal but I've read somewhere that Porsche designed the clutches for a 200k mile service life. Do you know if yours prematurely failed or did it just wear out from hard use? Glad things worked out even if it was pretty costly. The numbers you quoted are lower than the others I've seen so there's that. BTW, what's the Porsche core charge if you didn't return the transmission?

Originally Posted by Chris McSparron

According to the conversations Tony had with Porsche, he was told this is normal for higher mileage and a car that has seen track time. I just went through my tracks days since I owned the car, it's been on track 9 times in two years. I never manually shift, always ran in sport plus on track with traction control off. I did run slicks and Hoosiers, not sure that matters. My Cayman is a GTS and has a third radiator for trans cooling so temps never got above 270* on track. Unfortunately, this is what will happen to the PDK with track use. I would say that my car has seen mild track time, 5 times a season is nothing! Callace services a few race cars and said Porsche replaces the PDK's after a certain amount of hours of use on those cars if that says anything.

Tony Callace is a certified ZF technician and one of two qualified people to teach on the maintenance of these units and said as of right now they are not serviceable due to no available parts. I bought a remanufactured PDK directly from Porsche, they took my PDK back, it gets dropped off at a dealership and Porsche covers the shipping. I think the credit was around $2-3k? They did ship the new PDK to the states for free, although it takes 3-5 weeks. Expedited shipping is $1500.

Watch that oil leak from the vacuum oil pump, it WILL leak after track use since the internal piston gets worn out faster.

Originally Posted by subaru335i

What year is your cayman?
I still would not expect the clutches to wear out after only 9 track days that sounds like a bit of bull****. Sure dedicated race cars get their trans refreshed often but you aren't competitively racing and 80k miles is not that much.
I would be EXTREMELY surprised if this is supposed to be considered normal. All over Porsche talks about how durable these PDK with the Turbo S literally doing back to back launches until the driver was sick with no wear or overheating. I have also heard the 200k+ mile design life.

Also, Dodson makes replacement clutch disks I see no reason why flushing the fluid and replacing the cluches wouldn't be possible. They likely just didn't want to service or troubleshoot more and it is way easier to simply replace. Plus Porsche tells all of thesse "factory trained" mechanics that the only diagnosis is replace the trans.

I know there are shops in California and elsewhere that will open the PDK and install Dodson clutches.

Originally Posted by Chris McSparron

Cayman is 2015 GTS
my invoice had a PDK R Transmission part number, similar to the 987.2 Cayman R transmission

Callace Rennsport is an independent shop, they make their own decisions apart from Porsche. Tony Callace has over 30 years experience on Porsche's, ran the Porsche Le Mans team, and is currently one of two people trained by ZF to work on the PDK. He would have replaced internal parts if they were available or it was worth the time and effort. My transmission does not have replacement parts unfortunately. Maybe other PDK variants do, I don't know. I trust Callace Rennsport and his knowledge and experience. I spoke to LN Engineering after the diagnosis and they confirmed everything Callace and Porsche said regarding my situation.
I think your right about the PDK eventually being serviceable, but for now it is out of reach since there are no parts aside from some solenoids. Unless a shop has taken one apart, I don't know of any, I don't see it being an easy thing to fix anytime soon.

No shops will warranty any work if non-OEM parts are used either. Too much liability. My PDK is a remanufactured unit from Porsche with a warranty so I have that going for me. I wouldn't want to roll the dice on aftermarket parts for the PDK.

You can ask LN about all the Macan PDK's they've replaced this year, and those are street cars, it's a lot.

I've seen the video of the 911 doing launches back to back, that doesn't mean anything for longevity. Let's see that car after 80k miles.

Originally Posted by WrongWay

Hello,

First thanks to PV997 for sleuthing out all of this info and others for contributing! This thread is the definitive Porsche PDK source for info.

My problem: 2011 Cayman S PDK with 85K. 3rd owner unsure of prior track use. but have service records from new and was properly services (PDK fluid at 60K). I've put around 15 track days on it in the past year or so. Prepping for first event of this year and while changing COBB PDK tunes and doing a clutch relearn, I got a communications error in the middle of the clutch relearn. I've determined this is due to the TCU not accepting commands when it has a hard fault code. I don't think the COBB tuner caused the problem. Simply a result of the shift rods being actuated during the relearn. No matter the results are that the car is in emergency transmission mode and will not engage any gear.

I have the following error codes read via Durametric:
P0007 implausible signal. This is in the engine module indicating the PDK controller is giving an error?
1706 sensor voltage 5v too low
1732 shift rod 2 displacement sensors
C418 can fault, brake

It seems clear that I have a faulty shift rod sensor and I have limited number of options

• Replace the transmission with a unit from Porsche
• Try to order the Chinese parts, split the case and repair.
• Replace the transmission with a used unit

The car is at a trusted indie shop right now, they are getting me an exact estimate for the first option today, but the WAG is $15K total parts and labor for a reman unit from Porsche with a 24/24K mile warranty. They don't want to touch the Chinese parts or a used unit for the obvious reasons and I can't blame them.

My questions:

• Is a used unit feasible? I'm told the trans is coded for the car (VIN) and a used unit will not "transplant". Does anyone know if this is correct? If so where might it be coded and can that part be swapped between the units? From reading this thread, it would seem the brains is in the TCU, but it does not take much to encode a VIN number in an electronic component.
• I'm DIY'er enough to try to split the case and try the Chinese part, that seems simple to me, based on this thread. But I have never dropped a Porsche trans/engine before. Can it be done without special tools in a home garage with a set of Quick Jacks? My concern is i'll only have the car about 3 ft off the ground and will not have clearance.

Thanks for the help! Ken

Originally Posted by PV997

Hey Ken - Well first thing right off the bat is to understand that the PDK itself is nothing but a group of solenoids and very simple sensors. It has no smarts, no microprocessor, no knowledge of the VIN, or anything else beyond the PDK. All of that is in the TCU which is a separate microprocessor in the car. There really is no reason why a PDK transmission cannot be interchanged. A TCU will be adapted to the old PDKs characteristics (e.g. clutch wear) so that a transmission switch might not operate smoothly at first. However the existing adaptation can be cleared and the new transmissions characteristics relearned. I've seen many knowledgeable folks say a PDK swap causes issues (and I believe them) but I challenge them to explain how that can be beyond what I state above. The PDK transmission is dumb as a stump, all it does is react to commands and send simple data. These are completely standardized without variation within a given model. If you want to completely avoid this one can buy a new virgin TCU (no adaptation stored) but I would try first with the existing TCU mainly because I'm cheap and like a challenge.

I can get why your indy doesn't want to try the Chinese sensor but he won't even replace the transmission with a used one? Not even if you sign a release? We all like being in our safe spaces but this seems pretty extreme to me. If he's doing it at your risk why does he care? You'd be hiring him to do the work, not to certify the transmission. In all honesty it's the same thing with the Chinese remanufactured sensor. He's probably been burned in the past when expectations weren't clear. You might want to consider others if you don't want to DIY.

Search the forums for a clutch replacement on the Cayman as the PDK transmission R&R should be very similar. I know on the 997 it can be done on jackstands or a quickjack in the garage as many have done it (dropping the MT that is). I do think you are right that it's the distance sensor or the harness leading to it. In addition, the 5V too low could very well mean there is an internal short that is pulling down the voltage. I'd measure the resistance first, take a look at the figure in comment #216 which shows the pinouts. Measure between each of the sensor lines and +5 and ground. You can also measure it at the TCU which is easier to access but I'll need to look up the pinouts.

BTW, I'd say there is a fourth option which is to remove the distance sensor and repair it. It almost certainly has four linear Hall effect sensors in it each with its own pulse width modulation converter. If the sensor can be opened without destroying it that component can be replaced. The Chinese part is remanufactured so I'm virtually certain that is what they are doing.

Let us know how it goes.

EDIT: Here's the TCU connector in case you want to measure the distance sensor resistance there instead of at the PDK.