[Twodollardoug]

My wife has complained twice about our 2012 CTT alarm system. She says that when she presses the unlock button on the fob the front door unlocks normally, but when she presses the button again the other doors and the trunk don't unlock.

I remember a thread on another forum about the alarm siren battery going bad. I think Don our moderator has even dissected the siren module to find the corroded battery. But I don't remember the symptoms he had.

Don, do you remember what symptoms you were having? The first time she mentioned the problem I kinda blew it off but she mentioned it again today and it made me think of you and your siren. I found the part on porsche Marin for $206. If it is the siren I will document the fix and contribute it to the DIY section.

 

[deilenberger]

Since you have a 2012, and the battery in the siren is rated for 10 year life - you're due. Yeah, I dissected mine and found the battery had not only failed but also leaked on the circuit board damaging the wiring. You also can't disassemble the siren assembly without destroying it, so - a new one is the answer.

Mine had different symptoms at different times of the day, different days. Random. Sometimes the car would give an error beep on locking, and turn the flashers on and they wouldn't shut off without unlocking it again. Other times it would lock and then immediately unlock.

It's also possible the button on the door handle is going bad, although I can't see why it would unlock that door and not the others. People (Ed Lee for instance..) have had the button go bad and stay on continuously - which causes errors and IIRC prevents the doors from locking. The fix is to replace the switch/button, which apparently isn't available as a part without the entire handle which then has to be painted.. or snip the GREEN wire.

Those are the two things that seem to be consistent failure points on the alarm/locking. Other things like the starboard side rear door lock assembly going bad also are worth checking.

The siren is great fun to get to - ask my mechanic - the wipers have to come off, the plastic over the cowl comes off (not easily), then the wiper mechanism gets removed and THEN you can see the siren and remove it. A DIY would be great!

 

[Twodollardoug]

Thanks Don. My car doesn't have the button on the handle, so I can rule that out. I will have to keep an eye out for the emergency flashers staying on.

I agree. It's probably due for replacement.

One question, are the windshield wiper shafts splined or is it a keyway? In other words, do I need to pay attention to the "clocking" when I pull them off?

 

[deilenberger]

Thanks Don. My car doesn't have the button on the handle, so I can rule that out. I will have to keep an eye out for the emergency flashers staying on.

I agree. It's probably due for replacement.

One question, are the windshield wiper shafts splined or is it a keyway? In other words, do I need to pay attention to the "clocking" when I pull them off?

Splined. But if you mark the windshield (blue tape?) where they are when you take them off with them parked - they should work just fine if you put them back in the same spot.

 

[Twodollardoug]

Good thinking. Thanks.

 

[Raudi Driver]

Hi Doug, make sure you have a puller for those wipers. They can be tough to get off.

 

[Twodollardoug]

I have a typical 2/3 jaw puller. Is that what you guys are talking about?

 

[Raudi Driver]

I forget what I used but I think I just ran down to Harbor Freight and grabbed one.

 

[Twodollardoug]

Hopefully it won't be rusted on. I was planning on using my 2 jaw puller and being careful. I don't have a dedicated wiper puller. I think my rear wiper arm just pulled off by hand. So I'm hoping it's the same situation with the fronts.

I'm more concerned about the clocking on the shafts. Seems like every time I pull something that is splined I always get the clocking wrong.

I'm going to try Don's trick with masking tape.

 

[Twodollardoug]

 

[Twodollardoug]

Something like this would be a little less clumsy than my 2 jaw puller.

 

[Raudi Driver]

I couldn't get mine by hand. Had to use a puller.

 

[wirralbikes]

These may help if youve not tackled it yet.

(18) 2011 Porsche Cayenne 958 alarm horn repair. Its easy! (ish) I show you how. - YouTube

(18) How to replace the Alarm Horn on a Porsche Cayenne - YouTube

 

[kvec]

My wife has complained twice about our 2012 CTT alarm system. She says that when she presses the unlock button on the fob the front door unlocks normally, but when she presses the button again the other doors and the trunk don't unlock.

I remember a thread on another forum about the alarm siren battery going bad. I think Don our moderator has even dissected the siren module to find the corroded battery. But I don't remember the symptoms he had.

Don, do you remember what symptoms you were having? The first time she mentioned the problem I kinda blew it off but she mentioned it again today and it made me think of you and your siren. I found the part on porsche Marin for $206. If it is the siren I will document the fix and contribute it to the DIY section.

Doug, not sure what's going on there. You might use a scanning tool to read the signals live to figure out what's going on (assuming it's not throwing codes that would directly tell you).

In my experience, a failing alarm will throw a code or two before it actually stops working altogether. I've replaced my alarm 3 times now, finally breaking and putting in a brand new one, thanks to Don's discovery that what was failing was actually the battery.

I haven't had that specific set of symptoms yet, and I've had just about all the locking problems you can have: all the buttons on the doors shorting, the RR cylinder failing, and the alarm failing 3x, just off the top of my head. I've had some hilarious symptoms, like right now if you walk by the gas cap with the key in your pocket the car will unlock. I've posted in another thread here but replacing the door handles is making a huge difference in unexpected ways.

Bottom-line: You probably have to replace your alarm at some point soon anyway, but it's not obvious to me, based on what you said, that that's the culprit here. Would look at what the car can tell you about the electronics first.

 

[Twodollardoug]

I haven't had a chance to look into it yet. And the symptoms are what my wife is reporting to me so you know how that goes... We are driving to Vegas next week so I will be able to see exactly what the symptoms are. Thanks for the info. I will post back when I get a handle on it. Fortunately, my car doesn't have the rubber buttons on the handles.

 

[deilenberger]

These may help if youve not tackled it yet.

(18) 2011 Porsche Cayenne 958 alarm horn repair. Its easy! (ish) I show you how. - YouTube

(18) How to replace the Alarm Horn on a Porsche Cayenne - YouTube

Thanks for the DIY - the 2nd video (not yours I assume?) does show the wiper/cowl removal which is the most difficult part of the job. The hood has a service position - you disconnect both hydraulic cylinders and lean it back against the windshield. I'd suggest putting a towel between the hood and windshield, and if you're working where a gust of wind might slam it shut, using a bungie from the hood to one of the window frames might be a good thing to do.

 

[Twodollardoug]

I may just swap it as a preemptive measure.