And yet another key fob/immobilizer question

[JFP in PA]

Originally Posted by Gary_d

Searched every post on here, Rennlist and anything on Google. None seem to be the same.
The history: No problems with the Boxster for a long time, everything working well. Parked it in the garage for about a week and a half. Went to move it out the other day and it wouldn't start.
Symptoms: Turned the key on, everything lit up as usual. Turn to START, nothing.
What works: Ignition lights come on, radio works, horn, heater, etc.
What doesn't work:
1. Central locking and trunk switch from key FOB does nothing. FOB light flashes, but no response. Security light on dash does not light. Replaced the battery just in case.
2. Valet key does the same.
3. Central lock does not work from button on dash with either key.
4. Windows do not automatically retract when opening door, no raise or lower from the console buttons.
What I've done so far:
1. Battery voltage is good at 12.8 volts.
2. Disconnected battery to try for a reset
3. Checked all fuses for continuity with a voltmeter. Even the one on the Immobilizer.
4. Disassembled Immobilizer from under the seat (looked clean and dry), disconnected, cleaned and reseated connectors. Wiring harness looked good and intact. Cleaned circuit board with contact cleaner.
Codes listed from Durametric:
1. P1571: Immobilizer, open circuit or no signal.

Ideas?
GaryD

Yeah:

P1571 Immobilizer - Open Circuit / No Sign Possible causes: - Open circuit in wiring between DME / no signal. control module and alarm system. - Short circuit to ground or short circuit to B+. - Alarm system control module faulty.