Transmission temperature sensor, D-4 lights flashing
 

Lately my 2001 Boxster S tiptronic has been throwing a P0710 code. This is indicated first by my transmission selector lights flashing alternately between D and 4. Otherwise the transmission behaves normally, shifting up and down, in both auto and manual modes (not in "limp mode"). Information on this is sketchy. My durametric tells me that the code (P0710) is a Transmission temperature sensor fault. I would first like to check the sensor, a procedure which is briefly outlined in a repair manual ("Check sender for ATF temperature with wiring. To do this connect an ohmmeter to control module connector pins 21 and 22...etc.) Now there's a box in my rear trunk that's supposed to be the control unit but where exactly are the connector pins 21 and 22 located? Sorry if I seem a bit dense here. :unsure:
Seems that the fluid is okay. It was replaced in the spring. It may be the sensor. Had a hard time finding the right part number. Apparently you have to replace the whole wiring harness. The part is 4 hundred and change at Porsche, I found an OEM for 170. I'll try to figure out the electrical troubleshooting procedure first. Any input would be appreciated! :)

Double check your neutral safety switch, or adjust your cable slightly may fix it. I have Been working on my automatic trans for a while now and noticed even with everything perfect; if I adjust the cable slightly in either direction I get the D/4 flashing you are talking about. When you clear the code does it come back?
The TCU with pin 21 and 22 are located mounted on the rear walll in the rear of your car.

Good Luck please keep us posted what the fix was for future researchers.