stjoh

Yes, those (green and green/white) are called PRESS SENS 1 and 2 in the 987 wiring diagram. Red/blue is the supply (5V) and brown/white is the ground.



Here's the trouble code description too for completeness.

ss109

Analog 1 / Pressure sensor (Green) + Ground: Around 0.6 Ohm
Analog 2 / Pressure sensor 2 (Green/white) + Ground: Around 8.1 Ohm

Further troubleshooting required or have I found the culprit?

stjoh

I suggest you disconnect the connector at the transmission now. If you still measure a short then you have an issue with the harness, if not, I'd say you have a bad sensor.

ss109

Thanks for your help. Currently looking at the pinout. Assuming it's the same between 991/997?

ss109

@stjoh I am doing some last minute trouble shooting before dropping the transmission. I also have noticed these values:

Pressure Regulators Actual Values
1. 0.0 mA
2. 49.8 mA
3.725.8 mA
4. 551.3 mA
5. 44.5 mA
6. 44.2 mA

I also have the three following Pressures, Actual Values:
1. 0.0 bar
2. 1.628 bar
3. 2.360 bar

Should pressure regulator 1 be showing a value other than 0.0?

Also, from where are the three pressures sourced? I do not have a LSD, so should one pressure be 0.0?

Is it possible the solenoid pressure regulator (EDS1) has failed which is resulting in the issue with the pressure sensor?

byroncheung

Do we have a sense of how common are TCU or harness issues, compared to say distance sensors?

PV997

Have you tested the resistance of the solenoids? You might want to do that before you pull it, the expected resistances are in the main post.

It's possible that a bad solenoid could make the pressure readings look off (since the right pressure would not be supplied to it). However, it would not affect the resistance of the sensor itself which is clearly out of family compared to sensor #2. What's more likely is that the TCU realizes something is wrong with that pressure circuit and disabled that solenoid (i.e. no current supplied to it).

ss109

Sounds like you're right. Solenoid measures within range with a resistance of 5.3 O.

stjoh

If these measurements were taken at the gearbox connector with the harness disconnected I'd say you almost certainly have a bad #1 sensor. I guess it could be the harness within the gearbox too but that seems pretty unlikely.

stjoh

I'd expect to see some pressure on #1. If it's railed at 0.0 with no dithering it's another sign that the sensor is bad (I'd expect some dithering even if the solenoid was bad). Here's some data with the engine running in Park.

bschi

What an excellent guide about these magical PDKs. Well at least they have been magicall till demistifyed by PD977.

I'm also part of the broken PDK club since today. The error codes P1731-1734 indicate that there is some issue with the Speed sensor. As I still have Porsche warranty I hope to have some luck that they will replace the PDK with no cost.

Fullyield

Sorry to hear that. You are fortunate it is still on warranty. If you do not mind us asking: What year was your Porsche, what model (911, 981, etc.), number of miles and how often tracked. Any history of overheating engine and/or transmission?

bschi

120000km. 981s from 2012.
Never tracked, own the car since 2 years never overheated.

Does anyone know if porsche ensurance can discover my steering wheel mod? See my thread for more info

byroncheung

P173x are distance sensor errors. but regardless you should be getting a replacement pdk with the warranty, good luck with the repair!

Kuro Neko

At the convenience store, another on the flat-bed of shame.
The flat-bed driver said it was a complete PDK transmission failure (no gears selectable) and was taking it direct to Porsche head office.
Someone's looking at a big estimate, and hopefully finds an alternate solution via a few internet searches...