[PV997]

Exactly, that's why I was suggesting taking one apart and trying to identify the actual component, if possible. Guesswork isn't what's called for here.

FWIW, if the outer shell is aluminum, I can X-ray it if someone wants to send one up here (Pacific NW). That could potentially identify the part, or at least narrow it down.

Hi Noah - I've got an X-ray and I've taken one apart so we have that info. Unfortunately it's a very obsolete design that uses a large inductive pick-up coil, a bulky PWM IC, and lots of discrete components (times four as each channel has it repeated). It was probably designed at least fifteen years ago and it's just not worth copying it as there are so much easier ways of accomplishing the same thing with modern components.

Porsche/ZF used PWM as it has very good noise immunity and an engine bay is an inherently electrically noisy environment. On my 911 these lines run from the PDK to the TCU inside the car so it's probably a six foot run in a poor environment, PWM makes sense.

I've been emailing with jjrichar and we found a good PWM convertor IC but unfortunately it's only rated to 125 deg C (though it is specified for automotive applications). Looking to see if there's anything more ruggedized available.

Edit: Looks like I cross-posted with jjrichar. What he said!

 

[jjrichar]

Just tested the car again and they are all either 1040 Hz or 860 Hz plus or minus a bit, same as the other sensor by itself. PV, If you have accurate equipment I suspect what you are seeing is correct and I have an instrument error.

Also, duty cycle is either 21%, 50% or 79% for all plus or minus 1. Had the car in rolling test mode on the lift where I was able to run the car all the way through the gears and test. I'm not sure how accurate this would be considering the possible errors above.

For testing of the new HE sensors I guess it shouldn't make any difference. Just as long as the existing sensor and new do the same thing.

 

[schwinn]

@jjrichar (and everyone else): I emailed my best-friend/EE over the weekend, and just called him this morning... he was in a meeting, so I couldn't dive in deeper, but he says that there are other electronics in that chip already and he believes that we can generate a 1kHz PWM from that chip directly. I certainly didn't see that in my quick reading, but I will chat with him later on and get more detail on it... so don't toss out those chips just yet!

EDIT: He may have been talking about a different variant of that product line, and maybe I misunderstood, but we'll see... I'll report back as soon as I have a chance to chat.

EDIT2: Ok, so his statement was that there was probably a timer chip (eg a 555 timer) inside the epoxy as well, that generates the PWM. He said it's stupidly-easy to recreate that for our 1kHz PWM if we wanted. But he's feels it's silly that Porsche would go through all that trouble, and he thinks they are probably averaging the PWM on the car-side of things, and using that DC level to determine position. If that's the case, we can skip the PWM and just use the analog DC-level ourselves, saving ourselves the hassle.

So, to test this, the suggestion is to feed DC voltages into the car, and read the positions from PIWIS, to see if they correlate linearly. If they do, then that's what they are doing... and we, too, can skip the PWM completely. So, if you have a bench-top variable power supply, you can simply use that to feed voltage into the car at a few levels (eg 1V, 2V, 3V, 4V) and record what the PIWIS readings are at each level. I can detail the wiring setup further if needed.

Alternatively, if you don't have a variable power supply, then you can use single, double, and triple-battery setups and do the same (ie 1.5V, 3.0V, and 4.5V). Again, I can detail the wiring if needed... but basically you want the negative on the shared-ground-wire, and the positive will go to whichever signal-line you want to test.

I this test shows a linear relationship, then we have our answer, and can skip PWM. If they are really using the PWM in the car, then these would all read "0" or some max value, since our battery/power supply is only putting in DC voltages (ie, there is no pulse).

DISCLAIMER: All of this should be safe to do, as it's low voltage and well within the input levels of these signals. However, we are testing and doing this "off the reservation" and mistakes can happen, so I don't want anyone coming after me for damage caused to anything. I would feel comfortable doing these tests on my own car, but if you mis-probe or miswire, I don't know what could happen and bad things might happen. I just don't want someone coming after me for damages (the USA can be very litigious!)...

 

[jjrichar]

@jjrichar (and everyone else): I emailed my best-friend/EE over the weekend, and just called him this morning... he was in a meeting, so I couldn't dive in deeper, but he says that there are other electronics in that chip already and he believes that we can generate a 1kHz PWM from that chip directly. I certainly didn't see that in my quick reading, but I will chat with him later on and get more detail on it... so don't toss out those chips just yet!

EDIT: He may have been talking about a different variant of that product line, and maybe I misunderstood, but we'll see... I'll report back as soon as I have a chance to chat.

EDIT2: Ok, so his statement was that there was probably a timer chip (eg a 555 timer) inside the epoxy as well, that generates the PWM. He said it's stupidly-easy to recreate that for our 1kHz PWM if we wanted. But he's feels it's silly that Porsche would go through all that trouble, and he thinks they are probably averaging the PWM on the car-side of things, and using that DC level to determine position. If that's the case, we can skip the PWM and just use the analog DC-level ourselves, saving ourselves the hassle.

So, to test this, the suggestion is to feed DC voltages into the car, and read the positions from PIWIS, to see if they correlate linearly. If they do, then that's what they are doing... and we, too, can skip the PWM completely. So, if you have a bench-top variable power supply, you can simply use that to feed voltage into the car at a few levels (eg 1V, 2V, 3V, 4V) and record what the PIWIS readings are at each level. I can detail the wiring setup further if needed.

Alternatively, if you don't have a variable power supply, then you can use single, double, and triple-battery setups and do the same (ie 1.5V, 3.0V, and 4.5V). Again, I can detail the wiring if needed... but basically you want the negative on the shared-ground-wire, and the positive will go to whichever signal-line you want to test.

I this test shows a linear relationship, then we have our answer, and can skip PWM. If they are really using the PWM in the car, then these would all read "0" or some max value, since our battery/power supply is only putting in DC voltages (ie, there is no pulse).

DISCLAIMER: All of this should be safe to do, as it's low voltage and well within the input levels of these signals. However, we are testing and doing this "off the reservation" and mistakes can happen, so I don't want anyone coming after me for damage caused to anything. I would feel comfortable doing these tests on my own car, but if you mis-probe or miswire, I don't know what could happen and bad things might happen. I just don't want someone coming after me for damages (the USA can be very litigious!)...

Thanks for the input. I went and tested but unfortunately it gave an invalid signal with a DC source at the sensor output. No harm trying.

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 degC, and have programmable PWM and sensitivity. Hopefully it's going to be a relatively simple task of achieving the correct sensitivity and placement.

By PVs 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 only thing where I think we need some real help is the housing. PV is thinking that a 3D printed version would work well, but we need the input of someone with knowledge in this area to help out. Anyone?

Also, I'm going to change the thread title so it reflects where this thread is going, which is a community project to create an affordable distance sensor.



https://product.tdk.com/system/file...linear_hall-effect_sensor_with_pwm_output.pdf

 

[schwinn]

Ok, I'll sit back then since you have help in this now. I can contact my EE if needed, just let me know... but it sounds like you're on the right path!

 

[T-Design]

I would like to clarify that our price is going down every year, and currently it's well below $2000 for our partners indy shops, and comparable with Panamera distance sensor available from Porsche.

But! We include limited lifetime warranty on our 2nd gen distance sensors!

Thanks to our product, today the biggest cost of replacing sensor is in shop labor taking the PDK off the car.

 

[jjrichar]

Otherwise it really looks like some kind of crusade against small business, that makes parts superior to Porsche in quality and warranty, while comparable in price! Hope everybody understands that our resources are incomparable to Porsche, and it costs Porsche 10 times less (per unit) to make, support, and market parts.

My apologies if any offence has been taken with the posts above. I've amended those you refer to so any speculation has been removed. I've tried to be as objective as possible about the information I've provided. If there is something here that you think is incorrect or simply speculation, please let me know. Please understand though that the availability of information on anything related to the PDK is pretty thin, and the community is trying to gather what it can from what little is available. I was just repeating what I had read elsewhere online.

I'm certainly not on a crusade against small business. One of the reasons that forums like this one exist is for people to find alternative solutions to fix their car. What we are doing here is just that.

My personal opinion is that US$2199 for a replacement XemodeX sensor is far more than it should be. From our research it seems that a price that is a small fraction of this would be appropriate considering the cost of components, even at very low production numbers. We are just attempting to find an alternate solution.

To clarify, if I wanted to purchase one of your sensors to fit it to a car myself, what is the price? Your website seems to list the price of the other products you make but not the distance sensor. Your comments above seem to suggest your price is far lower than the XemodeX sensor. I think it would be valuable to the discussion to have this information.

I also want to clarify a few things for the general audience. This isn't speculation, but is based on my first hand experience. I bought a car to completely disassemble and make videos of everything I could. I was then very kindly donated a PDK to completely tear down and again make videos of every step. My aim was primarily to lift the veil of knowledge from these things and show that it's just not that hard.

The Porsche sports car is designed like nothing else I've ever worked on. If there is anything the project has taught me it's that the engineers who designed these cars did stunning job of making maintenance tasks easy, especially considering the engine is stuck in the middle of the car. I laugh at how easy sometimes. Having owned and worked on other cars made by the VW/Audi group, I'm amazed they all come from the same parent company as the contrast in how they are designed could barely be greater.

ZF transmissions are the same. I've pulled apart a few and I'm always amazed how easy they make something so complex.

Being able to complete tasks on the car is just a case of having the information and parts. All we are trying to do here is fill the information void that would otherwise be quite empty.

So to my points of clarification:

1. This is a 981 thread. For the 987, 981 or 718 the transmission doesn't need to be removed. Access to the distance sensor is easy. Exhaust, subframe, coolant and oil cooler (981/718 only). Remove rear casing. Remove sensor. Splice 6 wires. Install sensor and then put it back together again. Fill with coolant (981/718 only), start car, calibrate. Definitely a weekend DIY that's possible for someone who can turn a wrench in my opinion.

2. In the 911 the transmission needs to be removed. Yes, more work but not onerous.

3. There is a post on the Rennlist thread I referred to above by a workshop that say they have installed the T-design sensor. They quote a minimum of 28 hours of labour for a distance sensor replacement. Up to a maximum of 45 hours. Threads like this one here are to simply provide a possible alternative to this. Not just the labour cost, but also parts alternatives.

If you disagree with anything I've written here please let me know. I want to be as open, objective and honest as possible.

 

[T-Design]

It's true that on Boxter/Cayman it's possible to open PDK without taking it off the car. But, all serious shops still do. Not to gauge the price, but to provide a quality service. Opening PDK without damaging it beyond repair is not a trivial thing and it's much easier off the car. To ensure problem-free separation some shops use techniques that are impossible on-the-car. I mean you have a 60-80% chance that everything will be fine, but then you have 20-40% chance that case will crack trying to pry it open in limited space under the trunk... and then you are in for $20k. What do you do?

 

[jjrichar]

It's true that on Boxter/Cayman it's possible to open PDK without taking it off the car. But, all serious shops still do. Not to gauge the price, but to provide a quality service. Opening PDK without damaging it beyond repair is not a trivial thing and it's much easier off the car. To ensure problem-free separation some shops use techniques that are impossible on-the-car. I mean you have a 60-80% chance that everything will be fine, but then you have 20-40% chance that case will crack trying to pry it open in limited space under the trunk... and then you are in for $20k. What do you do?

I guess that's DIY in a nutshell. We take that risk every time we work on our own cars. Transmission, engine, convertible roof, it's all the same. But with care, patience and some decent information it's not hard. Everyone is a grownup and knows the risks.

I'm sure there are other weirdos like me out there who think that the pleasure of owning these cars isn't just the driving experience, but maintaining it as well. I simply have zero interest in someone else working on my car. As time goes on, these cars will be owned far less by people with deep pockets who are willing to throw money at any problem. Like the 986, they will be owned more and more by enthusiasts, who want to tinker and do it themselves. Forums like this with the information they provide are a lifeline for these people.

Even if I wanted someone to do the fix, finding a shop that knows what they are doing is difficult. Here in Oz I get nothing when I do an internet search. Just LN engineering in the US and Becks in Europe. The Rennlist thread I refer to above is littered with people having to truck their car interstate to fix the issue. And that's in a market as huge as the US. Putting my car on a float for a long trip and then be charged 28 hours of labour minimum is something I'm not interested in. I'm convinced there are others like me.

I'm not sure if you saw the question I asked in the post above, but do you sell your sensor to individuals, and what is the price? If you only sell to shops I can only assume the only DIY option that currently exists is from XemodeX for US$2199.

 

[PV997]

Adding a few comments here since I'm the author of the Rennlist thread discussed...

The entire point of that thread was to demystify the PDK and an attempt to stop Porsche's price gouging (there really is no other word for it). As an example, the clutch fluid pressure sensor costs about $100 and is even sold by Porsche dealerships since it's used in other vehicles. Yet if it fails in the PDK, Porsche will not replace it and insist you buy a new or remanufactured PDK (anywhere from $12k to $20k). If the PDK distance sensor fails, ZF will not sell you a new one as their contract with Porsche prohibits them from selling them to the public.

Porsche doesn't want anyone opening their PDK's at all and has done everything possible to prevent people from doing it. This includes withholding all information and embargoing replacements parts. Instead they insist you buy their authorized remanufactured PDK and have it installed at their dealerships. Their claim is that the PDK is too complex and that this work must be left to the "experts". As the Rennlist thread and jjrichar's posts here show, this is nonsense. The real reason Porsche does this is to create a cartel so they can control prices.

The DIY movement is a direct challenge to that. We don't accept the notion that we are too stupid, don't have the correct knowledge, the blessing of the guild, or whatever BS those that control the process claim is required. If they won't tell us how to do it, we'll figure out through open-source research, working on things ourselves, and good old common sense. We will then post that info so other like-minded people who think for themselves can do it to. When the Porsche Service Advisor (who is a commissioned salesman BTW) tells me I need a new $20k PDK then I'll laugh and walk out the door.

This isn't aimed at any company in particular, but there's a really annoying trend among suppliers that since Porsche is secretive and ridiculously expensive, then Porsche aftermarket suppliers are entitled to behave the same way. They aren't. Sure there are plenty of Porsche owners with more money than sense who never question this stuff, but many of us don't accept it. This entire guild system has to go too. Remember how Flat Six would only provide their IMS solution to a small number of shops they specifically authorized? They said they had a good reason for it (quality control), but in doing so they created an artificial scarcity. Whether intended or not, that creates a cartel that inflates prices for the entire process (both the part itself and the installation).

It's the same for the distance sensor or any other part where supply is artificially controlled. Fortunately in a capitalist system there are mechanisms that are self-correcting. Also, in this age with information at one's fingertips, folks with some smarts and ingenuity can usually figure out how this stuff is done. It's my goal to get that info out there so people have what they need to take control of the situation, no different from the open-source movement in general. There will still be plenty of people willing to hand over their credit card as they'd rather rely on an "expert" than think for themselves. However, for those who don't accept this, they have another option.

 

[T-Design]

The current price is $1890 on simple order to non-partner individual. But there are very few people who have the space, tools, software, and will to work on a PDK gearbox. Despite all the information for DIY repairs freely available and referenced right on our website - I think we had 2 people in 2 years who took on a task fixing PDK in the garage.

By the way, we do have partners in Melbourne, and in Brisbane. Not sure how they advertise but they surely do provide quality PDK repairs in Australia. No need to ship the car overseas

 

[schwinn]

Needless to say, I fully support the open-source, DIY mentality. I'm a degreed Mechanical Engineer, but that's not a requirement of any kind. My best friend is non-degreed, but we share the same mentality that we can really fix anything. As my day job, I worked in the semiconductor industry on multi-million dollar machines (the ones in cleanrooms). We dealt with NANOscopic particles (which we detected and COUNT), toxic gases, high voltages (over 350kV) and currents (over 400A), high and low temps (down around 10C abolute temperature), vacuum systems that were down in the millionth-of-a-torr, ion beams, radiation, moving machinery, automation, signals of all kinds, etc. Then I worked in healthcare building MRI machines (superconductivity, low temps, radiation, etc). I also have over a dozen patents to my name, for various things I created in the industry. I continue to work in automation, and I have my own company where I work on PLCs, robots, automation of all kinds, etc. Hell, I even programmed all the way back to assembly-language on some chips, not that I care to do that anymore... nowadays, high level languages are much easier to work with, of course. Anyway, you get the idea.

You can't possibly tell me that a car has ANYTHING more complicated than any of these systems... but we worked on these day-in/day-out. And we made them safe to use for operators who don't have any experience (or sense, sometimes) with these systems. I have always been able to fix or design systems that worked... every project I ran had a successful outcome with a product or device that delivered the operation required.

There's nothing magical about the PDK. It's a dual clutch transmission... the only difference is that it has two clutches and a computer controller. Mind you, "computer" in this sense is a low-power control unit, far less complicated than the robots or PLCs I normally work on. The only complication here is the lack of documentation on it, and the weird protocols used on it (eg a PWM for the distance sensor). Sure, there may be a good reason for PWM... but no one will tell us. That doesn't mean we can't reverse engineer it... nor should we be prevented from doing so. It's not magic... it's just a signal.

In the end, with or without degrees, we can all learn to work with these systems... and that's the effort I will always support.

I'm not saying that a vendor can't do this either... as we can see, we have one here that can. And they can take as much profit as they want as well in a capitalistic system. That being said, it doesn't mean we can't come together and find another alternative as well.

As for the complaint about the pricing... IMO $1890 isn't that different from the $2k that was mentioned before, so I'm not sure the "alarm" is justified. Also IMO, if the product is proveded at a lower price to indys and such, that's great... but if we DIYers can't get it then it's a moot point. Why the (artificial) restriction? Again, these are my opinions on the matter, so feel free to disagree if you want.

EDIT: I just want to be clear. I'm not calling anyone out, attacking anyone, or anything like that. I'm just stating various facts. I am in agreement with other DIYers here (and everywhere) that I'm tired of being told that I need to leave anything to "experts". I'll concede that the designing engineer for any of this stuff could certainly be an expert. But the mechanic working at my local dealer? No way... he/she may have access to documents (again, hiding info is just stupid) and maybe more experience, but they are not all science/engineering minded... so if something goes awry, they have no clue what to do next. I, on the other hand, can figure it out... and so can many DIYers. I have fixed MANY issues with my cars that well-experienced shops couldn't figure out... and the solutions were VERY dumb and simple.

 

[Noah Fect]

Nobody in this thread (including T-Design!) will ever have to pay for a beer in my town, I can tell you that much.

 

[Cayman Ed]

100% agree on DIY explorations. It benefits everyone even to those who go to Dealer or Indi shops for maintenance services and more so to DIYers like us. If you know about the subject matter a bit, they tend not to gouge pricing or screw you for other non-related services to max their profit.
Good to know that the PDK complexity is being cracked by passionate members of this forum. Thank you.

 

[jjrichar]

The current price is $1890 on simple order to non-partner individual. But there are very few people who have the space, tools, software, and will to work on a PDK gearbox. Despite all the information for DIY repairs freely available and referenced right on our website - I think we had 2 people in 2 years who took on a task fixing PDK in the garage.

By the way, we do have partners in Melbourne, and in Brisbane. Not sure how they advertise but they surely do provide quality PDK repairs in Australia. No need to ship the car overseas

Thanks for the information. I'll update the original post to reflect this.

Are you able to provide the names of the shops in Melbourne and Brisbane that you are partnered with? As an exercise I spent an hour ringing every non-dealership Porsche workshop in these two cities and came up with nothing.

 

[deilenberger]

100% agree on DIY explorations. It benefits everyone even to those who go to Dealer or Indi shops for maintenance services and more so to DIYers like us. If you know about the subject matter a bit, they tend not to gouge pricing or screw you for other non-related services to max their profit.
Good to know that the PDK complexity is being cracked by passionate members of this forum. Thank you.

This is one of the real benefits of forums like this - even if you're like me (too old to really enjoy scraping knuckles anymore), knowing what a potential fault might be caused by, and how to diagnose and then repair it, is really very valuable when going to a dealer or going to an independent shop.

An example - the 955/957/958 Cayenne V8 engines (up to around 2016) have a glued-in fitting on the cooling system that likes to let go, usually in the worst neighborhood at o'dark of night when your cell phone has no bars.

There are about 4 different ways this has been fixed by DIY'ers here on Planet-9 (and on that website I no longer participate in.) Some of us - being OCD - want to fix the issue before it happens, so we look at how best to do it. Porsche unabashedly, unashamed wanted $4,000 to fix it - drop the engine, replace the entire assembly, reinstall. I asked my local indy if he was interested in doing it, he looked at where it was located and showed a lack of interest in pursuing the job (doing it without dropping the engine means laying on top of the engine belly down and working back behind the cylinder heads - and he's almost as old as me.) So I contacted my other indy, who is a lot younger and a lot more flexible, and is familiar with this sort of fix (remove the piece, clean the bore it goes in and the piece, JBWeld them back together, with a pin or screw making certain the part can't come apart..) - and he tackled it without complaint. $400 later it was done. The nagging sniff of coolant I had for about 4 years was finally gone.

What would have been my alternative if I didn't have the hive knowledge of the forums? Pretty much spend way more money at the dealership.

That's why I love threads like this - we now know (1) the PDK can be repaired for some faults (2) there are parts available not from Porsche (3) there are writeups that a skilled mechanic could follow to achieve the repair (4) we have fellow owners and some DIY enthusiasts we can call on for help when we're left scratching our heads. (5) and some people may provide info allowing us to make our own part if we are skilled enough and have the equipment/parts needed to do it.

Right now - if my distance/sensor failed on my PDK, I'd be contacting T-Design for one of their parts, and then my trusted local indy - he's never been in a PDK box but I've seen him do amazing work with other transmissions, and I'm sure he'd do just fine with the PDK. If he didn't want to do it - my other indy races 987's, I'm guessing he's not a stranger to PDKs.

It's wonderful having this many alternatives instead of dragging off to Porsche for a replacement transmission that's 2/3rds the value of the entire vehicle.

 

[jjrichar]

After the discussion above I had to go and find the answer for myself. Can the distance sensor be removed safely with the transmission still in the car, and how long would it take? Was 28 hours minimum reasonable? Was there the serious risk of cracking the casing compared to having the transmission removed? So I pulled the distance sensor from the project car as though I was doing a replacement to see for myself.

I did the whole job easily in a day, and that was with me taking video footage etc, which always consumes a good amount of time. I’m pretty familiar with the car and transmission so I guess it would take someone who isn’t a little longer. You would easily knock it out in a lazy weekend. There just isn’t that much to do. Honestly, if you were doing this as a job and really familiar, I think you should be able to fully complete it in well less than a working day.

There is more space than you can poke a fat stick at to do the job with the transmission installed in the car. I also removed the bumper, including the metal bar behind and the heat shields. This all took less than an hour to get to the point where I was working on the transmission. Time well spent in my opinion. Have a look at the photos below. You can make your own decision on the amount of workspace available. If someone cracks the casing I suspect it has far more to do with technique and tools rather than it being still in the car.

In my opinion, working on a transmission doesn’t get any easier. If I had a preference I’d keep it in the car rather than remove. It’s like it’s stuck on the most solid transmission mount you can get. If the car was on jack stands you would just sit on the ground and it would be right in front of you. You wouldn't even need to lie down. Just sit there beer in one hand and wrench in the other. If you were a mechanic doing this all the time and very familiar you might leave the bumper on, but removing it and the heat shield above gives excellent access.

As you might be able to tell I’m a little stunned at how easy it was considering the noise from shops and others about how difficult and time consuming this task is. Trust me when I tell you there are many far more difficult DIYs in this car.

If it was a 911 it would take longer as the transmission needs to be removed from the car. I'm pretty convinced there isn't another 3 days work in that though. I might be wrong.

There was no need to drain the coolant. I just clamped the hoses, removed and plugged.

Test drove with the car on the lift using rolling test mode. Easy to just run through the gears back and forth over and over to test all is good.

I shot a bunch of video and I’ll put that together sometime soon. It will include the additional information I learned while working with it in the car.

 

[schwinn]

Awesome to see this progress. Again, I'm here at the ready to help whenever needed. I don't want to get in the way or have "too many chefs" so I'm staying out for now. I will be reading and following the thread with interest regardless!

The times allotted to work has always baffled me. For example, my wife's Jetta (inline 5 engine) needed a replacement O2 sensor. It's ridiculously easy on that car because of the inline arrangement - you pull the plastic cover off (1 clamp on the intake hose, and the rest pulls off the rubber grommets)... and it's clear as day and easily accessible from under the hood. Took me about 30 minutes to swap. The shop wanted 3 hours and $400 to do this (part was $100). And I'm older and less experienced than a shop... I just don't get it. Sure, shops should be able to make money on it, but this seems silly...

Anyway, back to the point of this particular post, I wanted to highlight the right-to-repair movement going around in the USA. We passed it in MA (when I lived there) and it's now gaining traction as a national movement, so I encourage all of us to support it. Check it out here: Learn About the Right to Repair — The Repair Association There are state-level movements as well, so support those if you can as well... the more states that can make this a thing, the better it is for the national movement.

Granted, this won't likely help us on these older cars, but things like PIWIS and specialized tools are directly targeted by this movement. We should be able to get the info to repair our own cars (and other items like cell phones, computers, etc)... there is no reason for this info to be hidden as it is today, other than to promote scarcity and increase prices. I encourage everyone to support this movement, so that indy shops can get the tools they need, and so that even we DIY-ers may be able to access the tools we need. Nothing in a car is "rocket science".

I mention this because I was with a fellow Porsche person the other day in-person, as we tried to get his headlight module coded for this Cayenne. He had never heard of this movement. I couldn't believe it... so I figure, this is a great place to mention it. Spread the word!

 

[jjrichar]

It's funny with auto transmissions, but there has been a reluctance from car makers to crack them open for a few decades now from what I've seen.

I did a project like this PDK one about 10 years ago, where I stripped and documented the transmission from my old E46 BMW. This was the 5HP19 also made by ZF. There was more information available than the PDK, but very little DIY work being done. The fluid in the transmission, was said to be 'lifetime', which is clearly rubbish, but in researching why I found the reason was that car makers didn't want dealerships opening up auto transmissions. They had seen so many warranty claims due to poor work being done by their staff they realised the best option was to not allow any work on them at all. They would do no transmission work at the dealership and just suggest an auto workshop to do the job.

Fortunately due to these transmissions being in many cars, including the original Boxster, parts were readily available from ZF. Also, due to the numbers of transmissions out there, companies like ATSG, Sonnex, etc provided information and alternative part solutions.

It all seemed ironic to me, as I also stripped and documented the BMW engine. The skills required for that were far more extensive than the transmission, and like the Porsche engine, there was extensive documentation and parts available for rebuild.

Whilst I think Porsche locking down the parts availability shows contempt for their customers, I also think there is more to it. At the risk of being flamed, part of me (a small part) understands why they have done it. I don't think it's just greed or malice. To me there a few things at play here.

1. Porsche don't do the training to allow to allow the work. Why? It should be clear from the what I've shown that the tools and expertise required are nothing special. I suspect the decision many years ago to stop work on auto transmissions now has created a void of knowledge that would be very difficult to fill. If Porsche were to supply the parts, then there would be the assumption they can provide the expertise to do the work.

2. The transmissions are extremely reliable, and so the need for corrective work is low. Whilst we are digging into the distance sensor problem here, when I was ringing dozens of Porsche specialty workshops the other day all around Australia, I didn't find one that knew immediately what a distance sensor was or its function. It clearly isn't a failure that happens often, even though it's the most likely failure point in the transmission.

3. Porsche licensed ZF to close down the availability of parts and information. This has clearly been discussed at length before. The thing I find strange about this is one of the best marketing tools Porsche have in my opinion is old models still driving the roads and being kept in good working condition. I was waiting the other day on the sidewalk of a shopping area and out the front was parked a 1980s 911 SC in really nice condition. It's not something you see very often where I live. A young couple, maybe early 20s and not obvious petrol heads, walked by and spotted the car. They knew exactly what it was. The looks of desire on their faces as they walked around and took it in was just plain funny to watch. I didn't expect this reaction because we are constantly being told the younger generation want an EV. You could just about see the 'I want one of those' thought bubbles over their heads. The MBA driven bean-counters at Porsche would prefer that their most desirable cars fail and be unfixable after a certain time period. Try and tell me that a normally aspirated flat 6 of the last 15 years isn't going to invoke the same emotion and desire in the years to come. The Porsche strategy of deliberately trying to get these cars off the road long-term makes little sense to me.

4. The number of PDKs out there is very low. Compare this to the latest range of 8 speed ZF autos that are in millions of vehicles. The motivation of companies like ATSG, Sonnex and others to provide information and parts for a PDK is close to zero because there's no return in it. Workshops are in the same position. It's only those that see a lot of these cars that have the throughput and knowledge that will confidently tackle the job. You will pay the price for it though.

So like is happening here on the forum, the knowledge and solutions are going to come from the community. Maybe Porsche will have a change of heart in the years to come and allow the sale of spares. I'm not holding my breath.

 

[jjrichar]

Video of the replacement procedure is in the OP for those interested.