It began with a Fully garded message, I had other nunerous codes 37 in all, from the alarm, to the SRS. I started with the voltage and downloaded the schrmatic off this site. A GREAT HELP. Thanks Matthew. I replaced the siren module, this removed my alarm messages, all I had left was SRS- AIRBAG, in...

Thanks, yes after looking at the S80 schematic, all things come back to the CEM. And with the complex nature it could not be as easy as just a swap.

Yes the gear position shows in the display as well as at the shifter, and goes through all gears while matching at both displays.

The serial # is 9485179 Just let me know. Also please read my post on my no crank on this S 80, TCM or Cem or other?
Is it possible an Alternator with an internally shorted diode could cause this?

I have several posts so far, Here is the story. Originally there was a no crank and Fully guarded showed in the message box. After several tests, I replaced the siren module. I now show SRS-AIRBAG service urgent. That is the only message left. I downloaded the wiring from this site, determined that ...

Tomorrow mid day, thanks.

Matty, could I get one please? I am the guy with the no start, S80 185K 1999. It's been giving all those pesky alarms over the last 6 months, now I have the SRS -Airbag, and a no crank situation. All else is fine. Do you think it could help? The siren replacement fixed the alarm service message. I a...

Update Sat 1/29/2011 siren module replaced. I still have the SRS- Airbag Service urgent in the message box. The Transmission shows to be in park, both in the display, and at the shifter. Replacing the siren eliminated the Alarm service alarm in the message box, also now if the vehicle is locked, and...

I have purchased the siren, I will install it tomorrow when I get to the coast.
I was expecting more than a siren,, and tjhought it was a module, so I removed the cover to the UEM.
any reasons why that needs to be reassembled & covered before I try a cold start?

I have the modules loose, there are two sealed modules, with a bundle of wires coming in at the bottom, and a bundle that splits in the front going to each module. Do these modules slip out? Is there a catch, or locking mechanism?
If not how do I disconnect and reconnect the siren module. Hard wire?

Sounds like we are draining a capacitor, I have not done that, so I will post the results tomorrow. I will try that before removing the module. I did find one for about $85 used. Thanks again.