When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I ended up buying larrytrk's 997 and figured I should keep everybody informed about the troubleshooting and (hopefully) repair in case it can help somebody else with the same type of failure. First I want to thank larrytrk for a great transaction, a true gentleman. This showed in the car too, very well taken care of.
When I got the car I connected my PIWIS and confirmed the codes:
P0730 Transmission Ratio Monitoring
P17F0 Transmission Overtemp Stage 1
P17F1 Transmission Overtemp Stage 2
P17F2 Transmission Overtemp Stage 3
P173E Transmission Shaft Input Sensor Speed Sensor 2, short circuit to B+ (exceeds limit value)
After clearing the messages I found that P0730 could be triggered by driving forward and back in 1 and R 40-50ft repeatedly. When triggered, gears could not be selected. The fault could be cleared but was again set by the same procedure. There was no indication that the temperature sensor was faulty and the actual temp was well below the threshold for the P17F0 code.
Using the trouble shooting diagram from Porsche for P0730 I could conclude that the three temperature codes are expected consequential faults for a P0730 and can be ignored. The P173E indicates an issue with Speed Sensor 2, consistent with the P0730 code.
I hooked up my PIWIS monitoring engine speed, vehicle speed and Speed Sensor 1 and 2 and started doing the back and forth (1 and R) maneuver again. Once again, the P0730 could be easily triggered. The failure always occurred when going forward in 1st. When doing a normal start in Manual mode the failure would post as soon as 2nd gear was selected. Each time the code could be cleared using PIWIS. The data showed that Speed Sensor 2 was flat-lined at zero rpm. This is consistent with P0730 and P173E codes.
Before tearing into the gearbox I wanted to make sure the issue was with the sensor, not the wiring or the TCU. To do this I gained access to the TCU and measured the speed sensor 2 wire for short to ground and power, no issues were observed. To fully verify the wiring and input stage on the TCU the pins for Sensor 1 and 2 were then swapped at the TCU connector. After starting up, both sensors initially functioned properly. However, when the temperature approached 50C Speed sensor 1 (actually 2 due to the reversed pins) started acting erratically and eventually flat-lined at zero. Lesson learned, when checking sensors ensure the gearbox is up to temperature.
I now feel quite confident that the issue is indeed with Speed Sensor 2. The next step is to open the case on the transmission and replace the speed sensor pack. More to follow...
Too bad this didn’t go when the temperature sensor went, last year and warranty would have covered it.
I miss the car, but, all’s well with the loss and it’s his gain when done!
Agree with all comments. Even the Indys (at least here in Chicago) are part of the 'successitis', so I don't think it is a HQ directive. The problem becomes people leave your brand, and then we all suffer.
Honestly, it gets to to the point that when I consider getting another P car, the first question is how do I deal with service issues? The options near me are terrible, so maybe its worth 'stepping' down for piece of mind with another brand/car.
Appreciate that DIY is a great option, but there are still times that I need to take it in, and it is painful to find, schedule, and complete the work.
Unless of course you are planning on moving to Chicago, Bruce?
I am impressed with the amount of work you have taken on. Kudos!
Got it all back together again today. While I haven't been able to do a long test drive yet the maneuver that consistently made it fail before does not any more. Both speed sensors now look normal again in PIWIS. It shifted fine during a short drive.
I will post a DIY later, probably in PV997s mega PDK tread. If nothing else, this shows that the speed and/or position sensors can be replaced with the transmission still in the car for the 911s too.
08-19-2023, 09:27 PM
