[T77911S]

not so far but you can test some more.
what wires do you have going to the starter? batt and alt on large post, yel wire on one post and you should have the power to the CSV on another post.

what i am thinking is you may have enough power getting on the yel wire to keep the solenoid egaged but not enough to pull it in on its own.
pull the yellow wire and with the key off measure volts on wire from wire to ground. you should have 0volts. (or use a test light). if the light is on, disconnect connectors until the light goes out working your way back to ignition switch.
the drawings i have are not clear enough for me to trace the signal but porsche uses the starter as a ground path of other things. i am looking into the above part some more.

or:
connect yellow wire back up. remove 14 pin connector at relay panel. (make sure it is connected correctly first. i think i put one on one set of pins off once). run test again.

i show 2 other connectors the yel wire goes thru. you could either test it disconnecting each connector or after doing the 14 pin connector(easy test) just goto the ignition switch and remove yel wire and jump starter..