PDK - P1731 & P1735 codes

[JT]

My 2013 Boxster S sat motionless for over a month due to a hospital visit, among other things. After I recovered and I renewed driving it, I started getting interesting warnings, e.g., “start/stop function deactivated’ or words to that affect. That progressed to “Fault engine control possible to drive” which evolved to something about “R no longer available, possible to drive”. That message would disappear after parking for an hour or so. Eventually, the codes continued and I had to erase them to keep moving. Finally I was stranded and had to call a tow truck and was towed to the Dealer – bad decision on 10/06/22.

The dealer discovered rodent damage, supposedly cleaned and corrected – $2,920 with no details other than this on the invoice:

Scan for codes check engine light. Vehicle will move on any gear. DME code P0660 intake manifold switch-over driver valve no signal due to rotten wiring damage. PJJK codes Pl731 disp. Sensor shift rods gear 4/6 implausible signal error. Pl735 distance sensor F shift rod gear 4/6 sqrt tern fault; clear codes vehicle moves. Possible internal transmission problems. Removed intake manifold center plenum in order to repair wiring damage by rats. Replaced intake 11/'s bifold switching valve. Pressure washed and disinfected engine compartment due to feces and rat urine. Install plenum runners with new seals and hardware. Clear codes, road test. During road test transmission hard shifting, scan for codes. DME P0700 fault in transmission control unit. PDK codes P1731 disp. Sensor shift rods gear 4/6 implausible signal. P1735 distance sensor F. Shift rod forward gears 4/6 short term. These codes are active. No reverse is available. Inspection of wiring to PDK control unit, no problems found. Fluid level correct. Intern:/1.l transmission failure not repairable; transmission needs replacing.

On 10/28/22, I had the car towed to an independent shop that I respect and has some experience with PDKs. They have worked on the car until today (11/10/22), but have come to a halt having no progress due the lack of information on PDKs provided by Porsche. They have discovered the following:

Everything is fine when the car is cold. Once it gets to normal operating temp, it starts popping codes in the PIWIS system. They have updated the transmission software and the transmission gear “re-learning” which completed fine. They suspect a sensor is bad, but don’t know which one or how to determine it. They know it is not a Valve Body issue. They are willing and ready to take the PDK apart, but need to know what they are looking for.

I am looking for any and all suggestions for next steps. I will monitor closely and respond to any queries ASAP.

[Jeff Alton]

Possible fault causes
- Line between displacement sensor 1 and PDK control unit faulty
- Displacement sensor module faulty
- PDK control unit faulty

Cheers

[manbridge 74]

I would be highly suspect of the wiring repairs, we generally have to replace the entire harness when it comes to drivetrain components with major damage to wiring.

We have recently replaced two PDKs in Panameras, 2018-19. The first was easy to diagnose as it had no reverse, so a new PDK. The second would get the “R not available” message and got a new Mechatronics unit first after consulting with Porsche field technical manager. This had no effect as fault returned. New PDK installed.

Not that I’m recommending it or know how they did it, but some of our clients have bought an aftermarket warranty in these situations.

[Jeff Alton]

I was simply posting what the Daig tree says could be a possible cause...
Yes, PDK to fail, we are replacing a 991.1 turbo one next week....

Cheers

[tdesign]

1731,1732,1733,1734,1735,1736 are the distance sensors errors. It can start intermittently, but will always progress to no-drive.

If you have one of those errors they are 100% point to a PDK distance sensor, and the distance sensor needs to be replaced.

Dealer will not do that as Porsche does not train them to open PDK, and does not sell the sensors. The only option dealer will offer is a complete PDK replacement.

But there is number of shops, in US and worldwide that now do PDK repairs at a fraction of a cost of new PDK.

And our company T-Design9.com manufacture the sensors. If you shoot us a line - we can connect you to a PDK repair shop in your area.

-Vlad, T-Design9