Wayne Smith

Reverse is on the odd gear shaft. Do you not have reverse either?

BucketList

Implausible means the pressure is not within the expected range based on the action taken by the controller. This could still be a sensor, wiring failure or a valve. In other words I wouldn't throw in the towel and buy a new transmission just yet.

PV997

Sorry that didn't fix it after all this time. Agree with BucketList and check out my original response at the top of the thread as I walk though some of the other possibilities. With a PIWIS you can stripchart the both clutch 1 and clutch 2 pressure sensors and see how they compare to each other, this might give you some clues if one is going flaky. Unlikely the dealership will do this for you as it's not part of their SOP, so you'll need to DIY or find a competent indy. Replacing the sensors requires dropping the transmission so it's not something to try without a firm diagnosis.

I can't recall, did you replace the entire valve body or just the solenoid?

Also, did the dealership have any issue calibrating it? Still curious why your shop was getting errors but I suspect it was because they weren't using an actual PIWIS.

Just notice it says "burning brakes" under may name on the left. What in the heck does that mean?

IDFB

A new valve body (OEM from dealership) was placed by the original shop, who didn't have a PIWIS so it was transported to the dealer for programming (P1872). The dealership had some issue clearing the P1872 (HITI error) initially until they replaced the fluid again. Now it's back to P17B1 and clutch 1 doesn't engage at all (including reverse).

PV997

Thanks for the info. That HYTI error has been a mystery we've seen two times now, your experience leads me to believe there was air in the system and the original shop didn't do the fill procedure right. The other guy who reported an HYTI error also said he got some funny messages during the fill procedure. It makes sense as the hydraulics wouldn't work properly since air is compressible.

PV997

@IDFB I know this has been frustrating but I'd really suggest you step back and reevaluate things before you go any further. It's easy for me to play armchair quarterback so hopefully these comments won't be offensive, but it seems pretty obvious the original shop was extremely incompetent (at best). They misled you about having PIWIS and then once they admitted it was some other tool, they wouldn't come clean about what they were actually using (based on your comments above). They apparently fouled up the fill procedure which caused all sorts of avoidable secondary problems which delayed the entire process. In addition, they threw parts at it (the valve body) without doing any true diagnostic testing such as strip-charting the sensors and solenoids which could have been done with a PIWIS. Please don't take this as I told you so (not the intent) but if you reread my comments at the top of thread I noted there are multiple potential different causes, and that while a solenoid was most likely, it wasn't definitive. Up in comment #5 I said that it was a crapshoot replacing parts without more data.

Again, this is not meant to be scolding and I hope it isn't taken that way, but I'd hate to see you spend more money on this without getting it resolved. I'd also hate to see you spend money on another incompetent shop's on-the-job training. At this point there are three options IMO, 1) ship the car to a known competent shop, 2) buy your own PIWIS clone, learn everything you can about about the PDK, and diagnose it yourself, or 3) replace the PDK. I'd do #2 but that's due to my engineering background and personality.

Keep us informed of how it goes and let us know if we can help. I've strip-charted the PDK using a PIWIS many times and am happy to walk through the procedure if needed. If you go that route you can post the results here and we can help interpret them.