jjrichar

This is something I haven't struck before.

Which type of cal did you do? Without part replacement?

The code you have is one that seems to indicate a distance sensor response is out of limits, but not beyond the limits that would give a 173x code. You said that prior to performing the cal you put in rolling test mode and it successfully ran through all the gears. So it clearly received an OK response from each channel when doing this.

The readings you are showing now indicate that no gear is engaged, as all distances are close to zero.

When going through the gears in rolling test mode, did you have the distance sensor indications showing in 'actual values' in PIWIS? I suspect not, but If you did, what distances was it showing for each channel. Did you ensure it was out of rolling test mode and all codes deleted prior to starting the cal?

What happens if you do this?
- Ignition on (engine off) then delete all DME and transmission codes.
- Start car, check codes. Anything there? It shouldn't have anything.
- Attempt to put into gear. Don't have in rolling test mode. Just select either D or R. Does is seem to select the gear OK without giving errors? Have the actual values for the distance sensor outputs in PIWIS showing and see what the outputs are.

Mirko Coletti

I initially do cal without part replaced, after several fail i tried with part replaced, but results is the same.
Unfortunately I didn*t have the distance sensor value while i was in rolling test mode. I'm sure that it wasn*t in rolling test mode, but there were some fault on ecu linked to not connected rear bumper (also a temperature sensor fail, it wasn't possible to erase that until I assemble the rear bumper)

I have now installed the rear bumper and tail lights and erased fault code (the only one that is ever there, is P1870)

I now will try the procedure you have described and i will update you

thanks much
Mirko

Mirko Coletti

I've done the procedure you suggest, after delete DME and PDk fail and start engine no one fault was there, try again calibration but same error.
even with no fault gearbox doesn't engage gear, with real time value on piwis they doesn't move when i put D,R N or P.

I have also programmed TCU and DME, all procedure is gone ok, but after tried again calibration, i have an other times the same stop at 58%.

I really don't know what can i do..

byroncheung

I don't think I have heard they reman with the upgraded components so from what I understand it is like-for-like and doesn't change the risk characteristics...

glennvdb

Hello all,

I don't believe this failure mode has popped in this thread yet, so here's a list of the fault codes in my 981 Cayman (07/2013):

• P1731 - Distance sensor information ¬ shift rod 1 outside validity range
• P1732 - Distance sensor information ¬ shift rod 2 outside validity range
• P1733 - Distance sensor information ¬ shift rod 3 outside validity range
• P1734 - Distance sensor information ¬ shift rod 4 outside validity range
• P173B - Transmission input shaft speed sensor, clutch 1 - short circuit to ground, to B+ or open circuit
• P173C - Transmission input shaft speed sensor, clutch 2 - short circuit to ground, to B+ or open circuit

What I think is special about this, is the fact that all these sensors seem to fail at the same time.

What can be the root cause? What checks can I perform to narrow down the issue? What can be the solution?

With the TL;DR out of the way, first of all: what amazing thread this is! Incredible to see how much knowledge and insights are gathered in this thread and in the videos of @jjrichar . To him and @PV997 , I have an engineering background in mechanics and have professional experience with electronics design, so more than willing to contribute to your 'open source' distance sensor project.

More details about my own case:

• 2013 981 Cayman 2.7 PDK SportsChrono with just over 100k km on the clock
• Spirited road driving, interleaved with long highway stretches and the occasional trackday
• Valve block replaced 2 years ago to resolve hesitating shift action. Done by 'The PDK Specialist' in the Netherlands (link), already referred to earlier in this thread
• Both PADM dynamic gearbox mounts have been replaced in the past 3 years
• Over 10k km of happy driving after the valve block replacement, including 2 trackdays. When cold the gearbox feels a bit 'stiff', but after a few kilometers everything is buttery smooth when necessary and agressive and direct when requested (e.g. in Sport Plus on track)

This summer I drove from Italy to Belgium to meet up with family and friends and joined a trackday at Spa Francorchamps while I was there (or was it the other way around?). Beautiful bucketlist experience. The car behaved exemplary, no issues whatsoever.

On the way home to Italy, in Switzerland, I hit a very subtle bump in the otherwise ultrasmooth surface of the Swiss highways. The message "Reverse gear might not be available" popped up and the car was stuck in 7th gear. Stopped the car, got out, waited for 10 min, restarted and got going again, without issues, for 3 minutes, after which the warning returned and I was stuck in 7th again. Pulled into a parking lot and was able to start the car once more to get it into a safer spot. When the towtruck arrived a few hours later, the gearbox did not engage anymore.

The car is now at my independent Porsche specialist in Reggio Emiglia (Northern Italy) and they are not experienced in servicing PDK gearboxes themselves. Begin an engineer myself, I feel the urge to ask for half a day's access to my car, bringing a multimeter, power supply and oscilloscope to their workshop to join them in diagnosing the problem. It remains to be seen whether they would allow me to do so.

My initial analysis of the 6 fault codes above was a cabling issue, messing with the grounding and/or power supply of these sensors, being all located on the same cable from the TCU to the gearbox. The workshop said they checked and all should be ok; I'm not convinced they thoroughly checked.

Reading through this entire thready (admittedly skimming over quite a few posts, it already took me 3 hours), the second hypothesis is the shifting rod displacement sensor failing, taking down the power supply in the transmissing ECU. Other ideas are a failed TCU or a defective cable between TCU and gearbox, or a damaged wiring loom inside the gearbox itself.

There are some other faults in memory as well, which I don't expect to be related. For completeness sake, however:

• P0700 - Transmission Control Unit Fault
• P1538 - Oil pump activation

Finally, I want to add that I expect there to be a mechanical issue somewhere in the drivetrain. At highway speeds, manually selecting 7th gear, at full throttle a mild pulsating vibration can be felt. Also on track this is noticeable. During normal driving it is not. This might mean that the gearbox has been exposed to excessive vibration, causing the gearbox issue that's the main topic of this post.

I'm very curious about the opinion of the highly esteemed people in this thread.

Thanks in advance for any input!

Glenn

Mirko Coletti

This evening after have read some post above that told to try much times to calibrate i have tried again. I have take off the battery and after about 3 hours i have tried. Distance sensor calibration performed 100% succesful, but clutch calibration 0% (in my opinion is because engine oil temp wasn't at 80° as requested).

Unfortunately i repeat a second calibration but it fails again at 58% of distance sensor so locked again in neutral.

Between the 2 calibration i've put car in P,R,N,D and all gears were engaged, i've take off battery again and tomorrow i will try again.

@jjrichar are this value below ok?

Distance sensor P

Distance sensor R

Distance sensor N

Distance sensor D

Calibration report

Clutch fail report

Clutch fail report 2

jjrichar

All of the distance sensor outputs look fine except for the one where D is selected. In this case you should see both 1st and 2nd engaged, meaning about +8mm on both channels 3 and 4. The distances for the gears that are engaged look perfectly OK. Less than 6mm or more than 11 is bad. The fact it's failing at 58% each time tells me there is a consistent issue that occurs each time as part of the shift rod calibration. But it worked once, so hopefully it should work again.

From my knowledge, the reason the clutch cal has failed is because you did a cal with part replacement, and this hasn't been completed successfully again. When you do a cal with part replacement, it wipes all adaptations right at the start prior to doing anything else. It doesn't do this with the cal without part replacement. You can see on the last image you posted that the cal has stopped because the hydraulic teach in hasn't completed. This is done as part of the cal with part replacement. I'm assuming the clutch cal failed immediately on beginning the routine, as I don't think it will even start attempting the clutch cal without a valid hyd teach in completed.

So I would suggest only attempting cals with part replacement. If it does the shift rod cal OK then hopefully it should complete the hydraulic teach in that follows, and then the clutch cal. It could take multiple attempts. If doing this, ensure after a failed cal you shutdown the engine, turn ignition on and clear all codes prior to starting engine and attempting the next cal.

It's unfortunate that you did the cal with part replacement, as once this is done the adaptations are wiped, and the only way to get them back is to complete the cal with part replacement. This can take many attempts as I've found before.

You may have seen the post I made recently on what is happening during a cal. If not, post #1323 above.

Mirko Coletti

This morning i have succesful completed all calibration.
@jjrichar if someone will have the same problem in future, i ve done how you have told me, with part replaced after the car car was battery off from 6 hours, engine and gearbox was cold, i've wait only for 60° oil gearbox, and start complete cal, it pass all at first time.
​i'm now at work so i can't test the car, but all gear engage and below i attached the new value in D. This evening i will test drive the car.



Richard your contribute it was crucial, thanks much

jjrichar

Super news. Well done. It was a long journey but it's great to see a good outcome.

porschafan

If anyone is interested im selling T9 Design Speed Sensor and Distance Sensor. I bought them installed on the car but never could do the calibration, so they are basically new. I will sell them with a good discount. Mods delete if not allowed. If anyone is interested PM

shantanugarg95

Hi, I’m facing the same issue with my 997 Targa 4s. After replacing the clutch and hydraulic unit I tried to calibrate the PDK and it failed saying Routine cannot be performed Threshold not programmed or programmed incorrectly. Car is not moving at all. How did you manage to get this fault sorted?
Thank

you

toddlamb

Sorry to hear of all the issues after sensor replacement, hopefully everyone is getting the picture that this isn't a straighforward DIY project. The EASY part is replacing the sensors, the HARD part (calibration and additional troubleshooting) is what comes after. Still getting calls daily to help owners and shops with calibration issues - unfortunately the only option is to start from scratch. Experience DOES matter here, there's no Porsche tax - you are paying for knowledge to get it done right the first time. Make sure the shop you are using has the experience and knowledge to complete the job when there are issues - there are only 2-3 here in the US that do.

shantanugarg95

Hi, are you using a clone version also? And can you please guide me with the process?
Thank you

glennvdb

Just for completeness sake, I'll add an update on my issue below, previously posted on "another well-known" Porsche-forum:

So, here we are, with a perfectly functioning car after absolutely no changes to the gearbox at all ...

Yesterday I went to the workshop I mentioned before to try and find the root cause of the issue I had.

• We connected the Diagnostics computer to the car and monitored the shifting rod positions while juggling the wires around the connector on the transmission, trying to trigger an unreliable contact, but the values didn't budge
• A visual inspection of the connector on the gearbox showed clean, non-corroded contacts on both sides.
• The same was true for the connector on the Transmission Control Unit
• We measured the continuity of the ground through the cable from the connector on the TCU to the gearbox and also this value was perfect.
• Also the PWM frequencies of the signals coming into the TCU while the car is running, were perfectly fine (2 times 1 kHz and 2 times 850 Hz)

So we weren't able to identify any faults in the cabling and signalling with the car on the ramp.

The next step was to go and drive with the diagnostic computer logging the relevant data, and much to my surprise the 20 minute drive with the tow truck in standby passed without any significant events (except for me getting emotional on how much I missed driving the car in the past 3 months!). Also looking over the data, we didn't find any strange behaviour for the monitored signals.

So this is more or less the worst possible outcome: we didn't find any issues and the car worked fine during a 20 min test drive, while I know that there is a problem lurking somewhere in there to rear its ugly head at the worst possible time. I cannot trust the car and I don't know what to do to increase my confidence again.

This evening or tomorrow I will take the car back home to free up space in the small workshop where it was in the past few weeks, and then the winter season starts here in Italy, giving me some time to contemplate on what to do next.

What would you guys propose?

Below some graphs from the report of the test drive (low quality; I couldn't get hold of the raw data ...).

The only thing I observe is that the values that are shown, are slightly offset. The three nominal values appear to be -5, 3 and 10 mm, so not centered around 0 mm. Maybe this is due to the fact that this is not a PIWIS but a generic Diagnostics computer being used?

jjrichar

Whilst you mention you measured the freq output from the sensor, did you measure the duty factor, as this is what the TCU is using for the distance? It does seem very strange that the distances are all offset like you say. It's an easy conversion algorithm for the diagnostic tool, as 50% DF will equal zero distance.

Here's what I would do.

Measure the sensor outputs at the TCU while it's in gear. First I'd measure with the engine off, as 1st will be selected on channel 3, and all the others shouldn't be engaged. Then I'd start the car and measure in neutral (all should have a DF of close to 50%), and also in D and R. D will select 1st and 2nd, and R will only select R. This can all be done with the car on the ground and not moving. You will get changes in DF for sensor channels 3 and 4. Channel 3 for 1st, and Channel 4 for 2nd and R. You should see around 22% or 78% DF with a gear selected.

I'd also be checking at the TCU the 5V and 8.5V supplies. If these aren't close to what they should be, disconnect the rear plug on the transmission (the one for the distance sensor and speed sensor) and then check again. You will get a bunch of codes but you can clear these once the plug is back on. This can be done with the engine off.

I'm assuming you have wiring diagrams and know the method to check all of these. If not ask and I'll post some stuff to help.