"P0841" Failure Code

[Eurocentric]

Greetings all. I am visiting the collective wisdom here for some answers. Recently I had my independant mechanic replace my ATF fluid and filter in my '04 S. I wanted to do this as I was about to take a long trip and would be towing a boat, and unfortunately had to have it done rather last-minute before the trip. The next day (hadn't left yet) the engine warning light came on. From my little code reader, I was seeing "P0841, transmission pressure sensor". I did take it back to my mechanic immediately. His first thought (and mine!) was that he had not put in enough fluid (something around 6 1/2 qts. I believe). He topped off the warm tranny, but the code returned later after he cancelled it. Since I was commited to this trip, I had no choice but take the car anyway. It performed brilliantly throughout mountain driving, and under load with the boat.

Any thoughts on what is going on here? I'd like to solve this myself if I can. Many thanks in advance!

[Loren]

:welcome:

It sounds like you have a stuck solenoid and/or oil pressure switch in the transmission. One or both are likely bad.

Best find a shop with a PST2 or PIWIS tester for further diagnosis.

[wvicary]

Your mechanic might have bumped the ribbon cable connector for the sensor which is causing a poor connection. Remove the pan again for inspection.

[Eurocentric]

Thank you Loren, and and thank you wvicary, very much. I believe I will visit my mechanic with your input. Again, many thanks!

[Eurocentric]

OH...forot to mention..the digital readout on the dash indicating what gear you are in is also non-functional (gives an odd little symbol instead). I'm guessing this may be an additional indicator that what your theory was wvicary? Again, many thanks to you both.

[wvicary]

The odd gear indicator display is to alert you to a gearbox fault, it should clear when you repair the said fault.

[Eurocentric]

Makes sense. Thanks wvicary!

[hahnmgh63]

I agree with wvicary, have your mechanic pull the pan and check the connections. Are you sure your mechanic knows the proper fill procedure and is measuring the correct temperature when doing it? 6.5 qts sounds a little light to me, I think mine took somewhere around 8~9qts but I did pull the pan and let it drain overnight.

[Eurocentric]

Hi hahnmgh63. Thanks for additional input on this. Yes, I am thinking more and more that they dislodged that ribbon cable that was referred to here by wvicary. I will indeed have him pull the pan and check it. And I could be wrong on the amount of ATF he put in. I quizzed him on this because he sounded a bit vague on things, which surprised me greatly, but I think he does know the importance of getting the fluid level correct. He's good with Carreras and Boxsters, but I've come to realize that maybe he doesn't know Cayennes as well as I thought. I am therefore (politely) offering input that I am learning on line from here and elsewhere. Cheers.