[Cbarrett33]

Hello all, I am a new member to the forum. I just bought my first porsche 9 months ago. While I was driving one night the car seemed sound like it "missed a shift" (loud clunk) and 3 error lights came on:
1.) Transm. Fault poss. No R gear drive on poss.
2.) Fault engine control possible to drive on
3.) Start/stop operation deactivated.

The car was stuck in 7th gear and I managed to make it the 10 miles home. Since then when I go to put the car in gear the gear indicater on the screen blinks (2) and it won't engage a gear. I pulled the codes and got these:

P1706 N/a
P0700 Transmission control system (MIL Request)
P1736 N/a

Has anyone had this problem? If so what ended up being the problem and the bill ?
Car is not under warranty unfortunately, although I did find the previous owners "CPO Card" in the glove box. Any help would be majorly appreciated. I am 2 hours from the nearest porsche dealer (dallas).

 

[deilenberger]

Can the device that you read the codes with clear the codes? That would be first step IMHO. You've recorded the codes so it isn't necessary to save them... and was this device running software that can read Porsche specific codes (any code > P0999 is manufacturer specific - ie - your P1706 and P1736,) I'd expect a Porsche specific tool to give an explanation of the code.

 

[deilenberger]

I just looked up the fault codes for a 987 PDK transmission. I expect the codes for a 981 PDK to be the same. There is no fault code P1736 for the 987 PDK, but there is one for P1706:

---------------------------------------------------------------------------

P1706

Diagnosis information - PDK

Sensor supply voltage 5 V too low

Diagnostic conditions
The control unit initially tests internal function sequences when the ignition is switched on (terminal 15). If they are OK, all diagnosable outputs are then tested and any faults are stored.

• Ignition on
• The following fault is not detected: P1752

Possible fault causes

• Line between pressure sensors and PDK control unit faulty
• Line between displacement sensor module and PDK control unit faulty
• Pressure sensor 1 faulty
• Pressure sensor 2 faulty
• Displacement sensor module faulty
• PDK control unit faulty

Fault setting conditions

• Sensor supply voltage < 4.5 V

Fault effects

• Gear held
• No R gear
• No emergency program diagnosis
• Transmission limp-home indication in instrument cluster control unit

---------------------------------------------------------------------------

There has been at least 1 reported incident of a PDK failure (987 PDK IIRC) which suffered similar error codes and they were cleared up by removing and cleaning and reconnecting the large multipin connector going into the PDK transmission. Cost to do that is 1 can of electronic cleaner (I'd suggest CDC MAF cleaner). This was reported over on RENNLIST. In that case the owner of the vehicle sold it inexpensively thinking they were facing replacement of the PDK transmission. The buyer (also a Rennlist subscriber) fixed it as above and hadn't reported any problems since then.

That would be my first step - read the codes using a Porsche specific tool (in this case - the Foxwell N530 with their Porsche module would be my choice if I couldn't get hold of a PIWIS - but I don't know how well the Foxwell will work with a 981.. it works marvelously well on a 987, The safe bet is a PIWIS of course.) I'd then use the same tool to read some of the values seen by the computer from the PDK such as communications between the first two items and the PDK computer.

Note: I am not an expert in the PDK transmissions - I just own one so I've kept an eye on tech data that's being revealed for the PDK transmission. There are a number of people and companies that are much more capable than I am with the PDK, and if I couldn't fix it with the simple steps I outlined, I'd be reaching out to them to see if they had ideas or someone/somewhere that could perhaps fix it. These are generally found on Rennlist, you can start on the 987/981 forum, look for the PDK sticky, and it will lead you to a much longer discussion in another model forum.

Good luck!

 

[Cbarrett33]

Awesome im gonna have it flatbedded to an Indy porsche mechanic in Dallas. I cleared the codes and they came back but its just a cheap code reader I bought to see if I could figure anything out. Once I get it down there, I'll let yall know whats going on. Yeah all the pdk replacement posts had me scared.
Thanks so much for the detailed reply!

 

[deilenberger]

Awesome im gonna have it flatbedded to an Indy porsche mechanic in Dallas. I cleared the codes and they came back but its just a cheap code reader I bought to see if I could figure anything out. Once I get it down there, I'll let yall know whats going on. Yeah all the pdk replacement posts had me scared.
Thanks so much for the detailed reply!

Sounds like a plan. As far as "all the pdk replacement posts" - so far I've heard of two PDK transmissions that were replaced out of pocket by an owner. There are also a few I've heard of that failed under warranty and replaced at no cost to the owner. Overall - from what I've seen here they're pretty reliable. And as far as not being repairable - that's Porsche making it difficult, but when Porsche does that someone someplace comes up with a way to get around the roadblocks Porsche puts up. I know there are clutch-kits available for the PDK, including kits for transmissions pushing more HP through them than stock. The valve body is available - aftermarket and from Porsche - and the control solenoids are available individually from China and I believe Porsche. If they were really unreliable there would be companies advertising their rebuilding/upgrading capabilities - the fact that there aren't to me indicates the lack of a market for those services, and that lack of a market indicates the PDK's are pretty reliable.

YMMV and I'm all ears on what your independent has to say.

 

[Arch]

Yea man that Rennlist sticky thread is such a great read! My Indy had a pdk out of a nicely set up track day 987.2 CS. It took one hell of a beating before something faulted, so they had it out and now I’m curious what came of it. I’ll drop by someday soon and update.

 

[maschinetheist]

Keep us posted OP, always curious what happens

 

[Cbarrett33]

Having trouble getting it towed to Dallas, having to get a trailer and take it myself, so it'll be at least next week before I get it down there but I will keep yall posted! 🤞

 

[Cbarrett33]

Okay so I got it to the dealership and they said its a temperature sensor in the pdk and ill need a new pdk /: my contact at the porsche dallas dealership is gonna try to get it covered under warranty. Not sure yet but I'm REEEEAAALLLY hoping so. (Car isn't under warranty unless prior owners CPO is still in effect. Found his cpo card in the glove box right before I trailered it.) I'll keep yall updated, prayers please 🙏.

 

[mrg02d]

Okay so I got it to the dealership and they said its a temperature sensor in the pdk and ill need a new pdk /: my contact at the porsche dallas dealership is gonna try to get it covered under warranty. Not sure yet but I'm REEEEAAALLLY hoping so. (Car isn't under warranty unless prior owners CPO is still in effect. Found his cpo card in the glove box right before I trailered it.) I'll keep yall updated, prayers please 🙏.

OMG this has been my worst nightmare...Just said a prayer for you! Hoping you find favor with Porsche!

 

[T-Design]

If it turned out to be

• Displacement sensor module faulty

Which fail quite often in older PDK - we have a solution. T-Design developed a complete sensor unit replacement. A new part that does the job better then Porsche part (desinged in 2007-ish). The original part is simply not available from Porsche. They tell you to replace whole PDK, at $20K, or if you can find a used one, probably from totalled car, and inheritably with same unit about to fail...

With our displacement sensor unit for 7DT45 gearboxes (PDK) - all is needed to find an indi shop that can open a PDK, and then it's a 5 minute job to replace the sensor.

PDK dispacement distance gear position sensor for Porsche 7DT45 7DT70 transmission

PDK dispacement distance gear position sensor for Porsche 7DT45 7DT70 transmission for 997 991 981 781 car models. Fix your PDK instead of buying new

t-design9.com

 

[Roni92]

Any update? Did you had to replace whole pdk? Damn one sensor fail and whole gb is toast? Thats f*cking ridiculous

 

[T-Design]

Any update? Did you had to replace whole pdk? Damn one sensor fail and whole gb is toast? Thats f*cking ridiculous

Not anymore!!! We have two cars running with our new sensors, and about half dozen in a process or repair

 

[ICNU]

Not anymore!!! We have two cars running with our new sensors, and about half dozen in a process or repair

do these sensors work on the 981 as well, or are we only talking about the older PDK units from the previous generations?

 

[T-Design]

It should work on all 911, Boxster and Cayman's PDKs. 981 transmission uses different part number, but essentially the same part.

 

[ICNU]

Good to know, thanks!

 

[Cbarrett33]

Okay update, im waiting on a new PDK to come from Germany. Looking like its getting covered by Porsche. Says it will take a few weeks to come in but im just happy im not out ~10k! Will update again once everything is set in stone!

 

[T-Design]

That is really the best outcome!
But usually those failures happen much later in car life, so the warranty is not an option. And it's more like $20 000 question, not 10

 

[Cayman Ed]

Not that I need it but it's good to know that there is a cheaper option than replacing the whole PDK transmission. What's the average time in hours from start to finish?

 

[Cbarrett33]

Update: okay sorry about not getting back to y’all sooner. They replaced the pdk, they tried replacing the control unit first but didn’t work. They covered it 100%. No questions asked, no back n forth. Just did it. Shoutout to parkplace Porsche in dallas, because I know they didn’t have to go to bat for me. Definitely will be buying my next car from them if possible. So all is running fine on the car, I’ve driven about 1,000 miles so far since getting it back and am super happy to have my baby back!