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More information on the distance sensor for those who are interested.
Big thanks to PV997 for his help over the last few days. There is clearly a massive brain on his shoulders and his knowledge is going to be key in making the project a reality.
Thanks for doing all these videos jjrichar, they are fantastic.
Unless you object, I'm going to ask the moderators to embed some of these videos in the relevant sections of the main post. (Unfortunately Rennlist doesn't allow author editing after a short period anymore, so I'll have to find a mod who can help out.) I'm pretty happy with where all this is heading. In just a few years we've gone from virtually any failure being a $20k replacement to people repairing these things in their garage. The low-cost distance sensor also looks very feasible, it amazing how modern Hall Effect sensors can completely replace ZF's original kludge design with less than 20% of the components. Hope to have more info on this soon.
Still looking for help with a housing, particularly from someone with industry experience. No pay involved, just a warm sense of satisfaction from helping fellow Porsche owners.
Thanks for doing all these videos jjrichar, they are fantastic.
Unless you object, I'm going to ask the moderators to embed some of these videos in the relevant sections of the main post. (Unfortunately Rennlist doesn't allow author editing after a short period anymore, so I'll have to find a mod who can help out.) I'm pretty happy with where all this is heading. In just a few years we've gone from virtually any failure being a $20k replacement to people repairing these things in their garage. The low-cost distance sensor also looks very feasible, it amazing how modern Hall Effect sensors can completely replace ZF's original kludge design with less than 20% of the components. Hope to have more info on this soon.
Still looking for help with a housing, particularly from someone with industry experience. No pay involved, just a warm sense of satisfaction from helping fellow Porsche owners.
More than happy for you to embed the videos in the main post.
Had a pdk problem that a shop managed to get it back to working order by doing a recalibration, but the problem just came back (for details of the original problem see my prev post https://rennlist.com/forums/997-foru...l#post18404793 . Symptoms/codes are same, only this time it hasn’t been re-throwing the code after I cleared it, also I can still get into reverse if I move between P/N/R for a number of times, like maybe on average 7-8 times… while last time reverse was pretty much dead and attempts to reverse will retrigger the codes and CEL)
While I suspect ultimately I’d need distance sensor replacement, for now I want to try recalibrating it myself see if I get it back to working order even temporarily.
Been reading some info about using PIWIS 2 to recalibrate, I have a few questions about it:
1. it requires engine and pdk reaching certain temp before recalibrating, can I get the car to those temp just by idling the car? (Since the car
can’t reverse reliably it would be easier if I can just warm it up and do the whole recalibration inside the garage)
2. can I backup current settings/values and restore them in case recalibration fail (right now car can drive forward just can’t reverse reliably, would be nice if anything goes wrong during recalibration I can restore current state)
3. is there more than 1 types of recalibration can be performed by piwis? I have read about a minor recalibration, vs. one for after part replacements (which I assume is considered major recalibration), and also heard the term “clutch relearn” floated around (which I suspect maybe is same as minor recalibration/recalibration without replacing parts?)
Had a pdk problem that a shop managed to get it back to working order by doing a recalibration, but the problem just came back (for details of the original problem see my prev post https://rennlist.com/forums/997-foru...l#post18404793 . Symptoms/codes are same, only this time it hasn’t been re-throwing the code after I cleared it, also I can still get into reverse if I move between P/N/R for a number of times, like maybe on average 7-8 times… while last time reverse was pretty much dead and attempts to reverse will retrigger the codes and CEL)
While I suspect ultimately I’d need distance sensor replacement, for now I want to try recalibrating it myself see if I get it back to working order even temporarily.
Been reading some info about using PIWIS 2 to recalibrate, I have a few questions about it:
1. it requires engine and pdk reaching certain temp before recalibrating, can I get the car to those temp just by idling the car? (Since the car
can’t reverse reliably it would be easier if I can just warm it up and do the whole recalibration inside the garage)
2. can I backup current settings/values and restore them in case recalibration fail (right now car can drive forward just can’t reverse reliably, would be nice if anything goes wrong during recalibration I can restore current state)
3. is there more than 1 types of recalibration can be performed by piwis? I have read about a minor recalibration, vs. one for after part replacements (which I assume is considered major recalibration), and also heard the term “clutch relearn” floated around (which I suspect maybe is same as minor recalibration/recalibration without replacing parts?)
1. Yes. There are no problems idling to get to the required temp.
2. From what I've seen, no. The calibration either works fine and finishes the procedure, with the new values then used. Or it fails or just stagnates and the old values are held.
3. Two separate procedures. One for a component change, and the other with no component change. It's pretty obvious in PIWIS. I've never used the one with the component change and I've heard that it wipes the TCM. I would not be using this.
The calibration with no component change will do two things.
a. Calibrate the shift rods. It moves into all gears, stores the response from the distance sensor and then uses that in the future to sense correct gear engagement.
b. Engage both clutches multiple times at differing RPMs to calibrate valve body actuation parameters for clutch engagement.
I'm thinking I might do a video on how to check the response from the distance sensor at the TCM. It's actually pretty simple if you have a multimeter that can measure PWM and duty cycle.
Lastly, and I'm not sure this is relevant. But when I disassembled the transmission, like the big magnet at the bottom of the gear section that catches all of the wear debris, the selection rod magnets that are used by the distance sensor were also completely covered in fine ferrous dust/sludge about 1mm thick. It was a pretty young transmission with only about 15,000 km. I've always wondered if this might have something to do with intermittent response from distance sensors as they age. Just thinking out loud. I can only assume this would be considered in design.
1. Yes. There are no problems idling to get to the required temp.
2. From what I've seen, no. The calibration either works fine and finishes the procedure, with the new values then used. Or it fails or just stagnates and the old values are held.
3. Two separate procedures. One for a component change, and the other with no component change. It's pretty obvious in PIWIS. I've never used the one with the component change and I've heard that it wipes the TCM. I would not be using this.
The calibration with no component change will do two things.
a. Calibrate the shift rods. It moves into all gears, stores the response from the distance sensor and then uses that in the future to sense correct gear engagement.
b. Engage both clutches multiple times at differing RPMs to calibrate valve body actuation parameters for clutch engagement.
I'm thinking I might do a video on how to check the response from the distance sensor at the TCM. It's actually pretty simple if you have a multimeter that can measure PWM and duty cycle.
Lastly, and I'm not sure this is relevant. But when I disassembled the transmission, like the big magnet at the bottom of the gear section that catches all of the wear debris, the selection rod magnets that are used by the distance sensor were also completely covered in fine ferrous dust/sludge about 1mm thick. It was a pretty young transmission with only about 15,000 km. I've always wondered if this might have something to do with intermittent response from distance sensors as they age. Just thinking out loud. I can only assume this would be considered in design.
@jjrichar thanks for your quick response, exactly the kind of info I'm looking for! thanks!
very interesting observation about the metal debris... my problem does seem to be intermittent, many instances of distance sensor problem I read here seems to be permanent so I was indeed very curious about if something is different with the intermittent ones...
My PDK failure occurred roughly 18 months ago (May/June 2021), with a DTC of 1734 (shift rod 4 displacement sensor; diagnosis performed using a Durametric). I had my car flatbedded to my usual local indy shop, and explained what I was seeing in terms of trouble code, and what the observed problem and solution was based on the information shared in this very thread. The owner of the shop insisted that he needed to perform his own diagnosis (which I understood), and he was certain that the problem could be resolved by recalibrating the software and communication between the PDK and TCU (to which I had my doubts, but was fine to let him proceed; the hope of which was that he would come to the same conclusion that I had, and would then move forward with replacing the distance sensor). No surprise, the calibration alone did not correct anything, and my mechanic’s next step was to send the car to the local Porsche dealer, as he was now certain that the problem was the valve body, which we know would not flag the trouble code observed. The car went to the dealer…. And sat. And sat. And sat even longer before they performed diagnosis. And when they did… No surprise… The car needs a new PDK because the distance sensor was no longer responding correctly (which is what I had told him from the start). I asked that the car be returned to my mechanic’s shop, and asked several times that he start looking into this (we’re at about 13 months in at this point). Finally the car came back to his shop… Where it sat, once again. I felt I had exercised plenty of patience with this guy… But every time I asked about getting started on the car, I was met with some excuse as to why he couldn’t. At this point (early Nov 2022), I had had enough. It was clear that my mechanic couldn’t do the job, and so it was time to do something about it. I got on the phone and called Beck’s European. A quick consultation to explain what I was experiencing, the diagnostic code observed, and the next step was lining up transportation for my 911 from CO to AZ. Laki at Shaughnessy Overland went above and beyond and had arranged to have a pick up on the very next day, with delivery on the day following (thanks Laki)! Car picked up Nov 11, delivered to Beck’s on Nov 12. On Nov 18th, the car was moving under it’s own power(!) and was now in the test drive phase for QC. After logging some miles on the car, it was cleared for release; my wife and I flew out on Nov 25th to pick up the car, and drove it 890 miles back to Denver!
A huge thank you to Frank, Kimberly and the entire crew at Beck’s European. They got my problem resolved in under a week…. After waiting for months, and trying to give my usual guy the benefit of the doubt… I should have just saved myself time and grief by just calling the right people for the job from the start. Lesson learned!
Picking up from Beck's. The moment felt a bit surreal...
Steady cruising rate on the Interstate... Vitals all looking good!
Electronic component selection is coming along nicely. We need some help in making a housing. It would be very much appreciated if there was someone with experience in the field (we are thinking 3D aluminium printing).
PV and I have been emailing offline about the problem and one thing we were concerned about was the differing PWM freqs of alternating sensors. So I swapped output wires for sensors 3 and 4 at the TCM (these have different PWM freq outputs) to see how the TCM responded. It read each as a perfectly valid signal within PIWIS and the distance was correct, just swapped around.
My conclusion from this is the TCM is looking for a PWM signal within certain parameters that is wider than the 860-1046 Hz range that I've seen from sensors. It then measures the duty cycle of the signal to determine magnet/shift rod position.
PV has ordered some sensors and programming kit that look to be suitable. Link below. They are good to 170 deg C, and have programmable PWM and sensitivity. Hopefully it's going to be a relatively simple task of achieving the correct sensitivity and placement.
By PV's estimation there is less than $15 of electronic components in there total. He's designing the circuit board, which he thinks he can get pretty cheaply, and then we need a housing and epoxy fill. The epoxy fill is easily sourced, but as stated above we need some help with the housing.
My PDK failure occurred roughly 18 months ago (May/June 2021), with a DTC of 1734 (shift rod 4 displacement sensor; diagnosis performed using a Durametric). I had my car flatbedded to my usual local indy shop, and explained what I was seeing in terms of trouble code, and what the observed problem and solution was based on the information shared in this very thread. The owner of the shop insisted that he needed to perform his own diagnosis (which I understood), and he was certain that the problem could be resolved by recalibrating the software and communication between the PDK and TCU (to which I had my doubts, but was fine to let him proceed; the hope of which was that he would come to the same conclusion that I had, and would then move forward with replacing the distance sensor). No surprise, the calibration alone did not correct anything, and my mechanic’s next step was to send the car to the local Porsche dealer, as he was now certain that the problem was the valve body, which we know would not flag the trouble code observed. The car went to the dealer…. And sat. And sat. And sat even longer before they performed diagnosis. And when they did… No surprise… The car needs a new PDK because the distance sensor was no longer responding correctly (which is what I had told him from the start). I asked that the car be returned to my mechanic’s shop, and asked several times that he start looking into this (we’re at about 13 months in at this point). Finally the car came back to his shop… Where it sat, once again. I felt I had exercised plenty of patience with this guy… But every time I asked about getting started on the car, I was met with some excuse as to why he couldn’t. At this point (early Nov 2022), I had had enough. It was clear that my mechanic couldn’t do the job, and so it was time to do something about it. I got on the phone and called Beck’s European. A quick consultation to explain what I was experiencing, the diagnostic code observed, and the next step was lining up transportation for my 911 from CO to AZ. Laki at Shaughnessy Overland went above and beyond and had arranged to have a pick up on the very next day, with delivery on the day following (thanks Laki)! Car picked up Nov 11, delivered to Beck’s on Nov 12. On Nov 18th, the car was moving under it’s own power(!) and was now in the test drive phase for QC. After logging some miles on the car, it was cleared for release; my wife and I flew out on Nov 25th to pick up the car, and drove it 890 miles back to Denver!
A huge thank you to Frank, Kimberly and the entire crew at Beck’s European. They got my problem resolved in under a week…. After waiting for months, and trying to give my usual guy the benefit of the doubt… I should have just saved myself time and grief by just calling the right people for the job from the start. Lesson learned!
Picking up from Beck's. The moment felt a bit surreal...
Steady cruising rate on the Interstate... Vitals all looking good!
You are certainly welcome! Glad your trip was smooth and thanks for your business. Happy motoring.
Electronic component selection is coming along nicely. We need some help in making a housing. It would be very much appreciated if there was someone with experience in the field (we are thinking 3D aluminium printing).
PV and I have been emailing offline about the problem and one thing we were concerned about was the differing PWM freqs of alternating sensors. So I swapped output wires for sensors 3 and 4 at the TCM (these have different PWM freq outputs) to see how the TCM responded. It read each as a perfectly valid signal within PIWIS and the distance was correct, just swapped around.
My conclusion from this is the TCM is looking for a PWM signal within certain parameters that is wider than the 860-1046 Hz range that I've seen from sensors. It then measures the duty cycle of the signal to determine magnet/shift rod position.
PV has ordered some sensors and programming kit that look to be suitable. Link below. They are good to 170 deg C, and have programmable PWM and sensitivity. Hopefully it's going to be a relatively simple task of achieving the correct sensitivity and placement.
By PV's estimation there is less than $15 of electronic components in there total. He's designing the circuit board, which he thinks he can get pretty cheaply, and then we need a housing and epoxy fill. The epoxy fill is easily sourced, but as stated above we need some help with the housing.
We need a CAD model of the housing to speed things along (electrical design, component selection/programming, PWB design/fab, and potting are already all covered). My CAD skills are pretty rusty, if anyone is CAD-fluent and can help out with a 3D model please PM me.
Caveat: this is a community crowd-sourced project and not-for-profit. It is not a business offer.
PV997, thank you for trailblazing the path for PDK repairs and bringing this topic to light! I for one am very thankful that my gearbox could be repaired with a new distance sensor, and didn't have to replace the entire PDK!
jjrichar- also appreciate your videos and demos that you have put up on YouTube! I am a very visual person, and it has been very interesting to follow along as you show how the parts disassemble, and how everything works together! Thank you for taking the time to put those videos together!
I too self-diagnosed as per here, sourced a shop I'd never contracted to before, and fix time was similarly less than one week (less shipping time from T-Design to Japan from the US).
As per a number of comments above, knowing a competent shop who can apply some thought process to what is needed is key... Rote repairers are useless.
Video below of a distance sensor replacement in the 981. Very easy access with the transmission still in the car. A few photos also showing the access you can get with less than an hour of effort. Thanks to Neko's photos for inspiration. I removed a few more items than shown in his photos just to see how much access I could get. Not a particularly difficult DIY as you will see. You'll need to knock out a simple home made tool, but nothing extravagant. It took about 2.5 hours to get the cover off and get access to the sensor. A day in the shed and no more in my opinion.
11-27-2022, 01:33 PM
