Just bought my 991 a few weeks ago. Several times already, after the car is parked, engine off, locked up, the 4 way flashers mysteriously go on completely out the blue. If I hit the FOB to unlock the car and then lock it again, they go off, but half the time they come back on again a few minutes later. And they'll go on whether the car is locked or unlocked.

Any idea what this might be? Anything alarm system related?

And yes, the 4 way flasher switch is off.

 

How old is your battery? This usually a sign to change battery.

 

August 2019. No other sign that the battery is weak. Car's been sitting for 5 days, just checked the battery voltage and it's at 12.4v.

Forgot to mention -- a few days ago, the alarm siren went off for no apparent reason. I did an Unlock and Lock with the FOB and it never happened again.

Is the system designed to set off the 4 way flashers when the battery is weakening?

 

Rennlist post on this. Alarm Module issue maybe

Emergency Flasher Issues

my google search
Porsche 991 emergency flasher come on automatically

And this from 6Speed

and this is interesting

It's the alarm module. Has a NiCad battery in it with a 10 year life - at 11 years it goes bad and those are the exact symptoms. The fix is to replace the alarm module. On a Cayenne it's located in the cowl area, dead center, under the windshield wiper mechanism. Figure 2-3 hours labor. The battery is not replaceable, and the unit is sealed for your protection. No idea on labor for a Panny..

 

I had the same issue last fall. I replaced the alarm siren and it fixed the problem. See: https://rennlist.com/forums/991/1314...en-locked.html

Martin

 

Just the siren, or the module too?

I believe the module is much harder to access.

 

Thank you, Silver, that was all very helpful.

 

I only replaced the siren. I may be mistaken but I believe the alarm siren and alarm control module are one part in the 991.1.

Martin

 

If I'm not mistaken, some frunk latches had issues too, causing a misread on whether it's open or closed. That could be why the alarm is sounding or when the lights would flash.

Examples, thinking it's opened after the car is locked, or when its late registering closed after the car is locked.

 

That would be good news if that is the case, since it's such a simple DIY to remove and replace. Elsewhere in the posts around here, they refer to two separate parts.

Who did you order the part from? Part #?

 

These same sirens / modules are used by numerous vehicles. VW /SEAT/ Audi / Skoda etc.
If you want the exact part and revision number in your car, you can take a peek in your frunk.(It simply snaps into a bracket which is held on by a screw.)
I got my replacement on ebay.

 

Full details are in the thread I linked: https://rennlist.com/forums/991/1314...en-locked.html

The part number on the alarm siren I removed was 1K8 951 605 B. The one I bought was part number 1K0 951 605 C as in the picture. The ad said:I got mine on Ebay for $37.77 including shipping and tax.

Martin

 

Was that used or new? I don't see any new ones for anything near that price. Around $90 for a new one. I definitely want a new one.

 

Used. Still working a 15 months later.

 

OK, just ordered a new one from Ebay. Should have it in a couple of weeks. Hopefully, it solves the problem.

Thanks everyone for your help and suggestions.