MIK911

Starting 2 wks ago, my 2011 Cayenne alarm would blare when armed, but no intrusion. Repeatedly blares despite unlocking/locking, and making sure all doors/windows closed, etc. Of course this only occurs randomly.
Brought it to dealer, who said they couldn't reproduce it, so gave it back to me. Said they ran 'diagnostics' and came up with nothing.
Of course it's happening again.
Searched here, and there was some mention of microswitches in the doors that may go awry.

Any ideas?
If a door sensor or microswitch is 'broken', would this be detected in the 'diagnostic' evaluation?

thanks

Andy E.

In most cases, this is a faulty interior motion sensor. Try following the steps below for a few days to see if in fact this is the source of your problems.

I'm not sure about the 958 however, on the 955/957 there's an on/off rocker switch for the interior intrusion detection system, which is mounted at the bottom of the B-pillar. Check your owner's manual to see if your car has one. If so, try turning off the switch when exiting the vehicle; although you may have to do this every time you exit your car, since the system resets automatically.

You may also be able to deactivate the system through the multi-function display.

ScootCherHienie

Also, you don't have a dog inside the Cayenne when the alarm is going off, do you? If so, the dog is stetting-off the interior motion detector. Ditto what Andy E said. Assuming Porsche continued to install interior motion sensing after the 2010 model year, you should have a means of disabling the motion detection (the push button Andy E mantioned is used for 2010 and earlier). You can leave a dog in the Cayenne if you remember to disable the interior motion detection each time before you lock the car (or walk away and it locks itself if so equipped).

MIK911

Thanks but it's not the interior motion sensor. On one occasion, the occupant turned off this switch, yet the alarm still sounded. No dogs or animals during the other occasions.

ElTorrente

Maybe you have a mouse living in it?

Petza914

My 09 TTS does this sometimes too, maybe 1 out of 5 times. I haven't been able to trace it to anything, but also haven't Reyes disabling the interior motion sensor. Let me know if you get to the source of yours.

dapopa9

@MIK911 did you ever find the root cause or solution? My 2011 alarm has went off a few times randomly the past 2 days.

raydog9379

Mine does on my 2016 every once in a while, not sure what my wife does but she's good at making it go off. Will do it almost every time if I hit the button on the door handle though. It takes about 30-60 seconds before it goes berserk.

Imagine I should get it checked out at some point.

CAVU

in the late summer of 2016, my 2011 CS was doing unusual things, including the alarm just going off for no reason. Suspecting the AGM battery, I tried charging it, nothing unusual for a few days and then the usual-unusual would start up. in 9/16 I replaced the 6 year old factory AGM battery with an AdvanceAuto H8. Things went back to normal and have been every since.

What I never tested, and in hindsight wished I had, was to disconnect the battery via the negative cable (carpet cut out in front of the driver's seat) and then reconnect. Hard reboot of all of the systems to see if that would resolve the problem. You might try that first.

These modern vehicle have 30-40 "modules" aka computers in them and they are VERY sensitive to voltage fluctuations and electrical noise. As good as AGMs are, they are still just batteries with all of their weaknesses. Yes they do seem to last longer, but how they die seems to be slower . You can drop by your preferred auto parts store and see if they will test the battery via the engine compartment jumper connectors.

Good Luck!