Originally Posted by dollarlongnecks

So I didn't change the wiring once I got in there. I just cut that plug off and used those two leads to connect the 12v alarm siren.

If you are planning to do the swap from the battery backup version to a basic siren, I would imagine the necessary wires are unused and tied-up in the wiring loom under the dash. The wires have to come through a grommet in the firewall, and I'm pretty sure if you get under the dash on the drivers side you should be able to find that loom and locate the necessary wires, then pull them through to do the hookup.

Originally Posted by cathalferris

Question: If the car is "7AC ALARM SYS., INTERIOR SURVEILL. ALARM HORN" from the VIN decode, then it *shouldn't* have the failing alarm module, as there's no "backup horn" listed? I haven't yet had reason to disassemble that part of the engine cowling to verify.

On one hand, it's a little worrying that my car doesn't have the best of the available security features, but on the other hand the security should be good enough and there appears to be a lack of a known-failing module.
(https://www.forum-macan.com/forum/viewtopic.php?t=14884 - the latest post of the thread 2020 Dec 16, appears to have a nice listing of the possible alarm options as per the VIN decode possibilities.

Originally Posted by garrett376

Interesting... so in effect, with no terminal 30 hookup, you are not charging the backup battery in the module, so it is likely discharged completely and you're just using its speaker function. I wonder if that small battery is enough to drive the entire alarm system for a period of time, even with a dead main battery? It must be able to, to make its design worthwhile.

Originally Posted by dollarlongnecks

I spend the last few days snowed-in, so I decided to tackle this alarm siren replacement, which I'd been planning for (er, thought I'd planned for). All the trim off, wiper motor out, and instead of the normal alarm module, there is one of those old-school Bosch metal disk horn/siren things. Once I get that out, I see the plug and wiring are different, so I start unwrapping split-loom looking for the other wires. In the end I can see that a ground was added, and a new wire was introduced, but all the wires that would be present for the alarm module are missing.


So my Cayenne was originally equipped with the alarm depicted on the left (verified via VIN) - which is the unit we're discussing in this thread - and at some point before I became the owner, it was physically rewired - and the module recoded - to be setup like the alarm on the right. It was done professionally, probably at the dealer, as all the wire splicing is done with water-tight heat-shrink and it's all very clean and factory looking. I'm assuming the wiring loom under the dash contains all the necessary wires for either setup, so they likely just pulled the unused ones back inside through the grommet in the firewall, and pulled the one new one out.

I considered getting under the dash and trying to find everything to rewire it - and I'd already found the coding location - but I started wondering why they went to all this trouble to disable it... This was not a simple change-over, as there was a lot of wiring work done in that little space, plus the required coding. The obvious answer might be the known failure rate of the alarm module made someone decide it wasn't worth it long term, but I started to worry there might be other, unknown electrical issues, like maybe something with the LIN network... Anyway, I figured someone made this decision for a reason, and I wasn't ready to find out how many reasons there might be.

So I took a car alarm siren I had, a DEI 514N, and wired it up in place of that metal disk, and now it works like a champ and doesn't beep like a dying animal. It's got that normal alarm "soft chirp" when arming, and when the alarm goes off, it's... interesting... Previously, the alarm would "honk" that disk horn every second or two, but now the new siren starts it's "wee-ooo-wee.." and then cuts out and starts it again so you only get the first few notes of the tone. It's unlike any alarm I've heard go off, so it will definitely be noticeable.

Anyway, the reason for this lengthy post is to let everyone know that if you don't want to worry about these modules dying, you can remove that alarm and replace it with any normal siren - you'll just need to do a little wiring and some coding... I'm sure a dealership could do it as a request, but not sure what that would cost. I would guess 2 plus hours for labor, less than $100 in parts maybe.

Originally Posted by CS958

Was there a specific reason you wanted to get to this alarm "module" other than the dead animal sound of the "chirp?"

Originally Posted by CS958

So I thought it must've been the leaky battery, especially given that it is right about the 10 year mark. So I ordered the latest iteration of the part and even supplied my VIN to 2 Porsche dealerships. They both said it would fit, not mods, no adapters.... just plug and play.

I spent two hours taking apart everything to find this silver disc siren, just like yours. Mine is a 2012 that was ordered brand new from the dealership. So it actually came factory equipped with this disc horn.

Originally Posted by kvec

If you search "Alarm" on this forum, you'll see the symptoms that cause people to go searching. The flashers start after you lock the car and don't stop until the battery dies. Once it fails, you're SOL in a minor way. The only way to fix the problem is to fix the root cause, which is the failed alarm module. It doesn't allow the central locking system to run properly, so the car thinks there's a problem.



Did you try swapping out the horn for the new module? I've gone through 3 alarm modules on my 2011 CTT. The original one made the honk. It failed. I replaced it with an ebay-sourced model off a wrecker. It worked but eventually also failed, so I finally just bit the bullet and replaced it with a new OEM module. Mine's a MY older than yours so I'd think yours could probably have the same thing.

Originally Posted by CS958

Was there a specific reason you wanted to get to this alarm "module" other than the dead animal sound of the "chirp?"

My alarm was dying exactly how everyone here with a leaky battery with an actual module; It intermittently would not make any sound when arming, the range was going to crap and the alarm would sound when the door was opened with Keyless entry. So I thought it must've been the leaky battery, especially given that it is right about the 10 year mark. So I ordered the latest iteration of the part and even supplied my VIN to 2 Porsche dealerships. They both said it would fit, not mods, no adapters.... just plug and play.

I spent two hours taking apart everything to find this silver disc siren, just like yours. Mine is a 2012 that was ordered brand new from the dealership. So it actually came factory equipped with this disc horn.

In your diagram, what is this rear BCM unit? And is that the true "alarm module" since there is just a horn where the module is suppose to be? I'm still trying to hunt down the reason why the alarm is slowly dying and bugging out, even without a leaky NiMH battery inside a module I don't have.
In other words, there must be an alarm module elsewhere, since there is just a horn where the module is supposed to be.

(And word to the wise, if your siren sounds like a low-pitched groaning honk instead of the high-pitched modern "beep," you have the disc horn. So if you are opening everything to get to an alarm module to swap it out, don't waste 2+ hours like me just to put everything back)

Originally Posted by CS958

I have the latest unit (PAB-951-605) on hand when I took everything apart. I even contacted 2 separate dealerships along with providing my VIN to the supplier to make sure I would not run into the situation where there was a wrong part. This was to no avail, as I found this sliver disc siren instead of the black module that most seem to have (I'm guessing, including your 2011 CTT?).

*I red circled the silver-disc horn from the pic provided by Garret up top**

Seeing this silver disc, I decided to unplug and check the harness anyhow, since I already did all the work to get in there. It is a 2-prong harness vs the 3-prong on the Alarm Module unit I had on hand. And the plug would not fit anyhow, which leads to me to think that there is another alarm module in a different location. This location, there is only a silver-disk, which is a horn only (the dreaded-dying animal groan-honk). I'm guessing yours is a black plastic module, right? It's weird that Porsche had some 2011+ models with the black box module and then some random ones in between with the silver-disc horn and no module.

My theory is that they had some parts shortage during production and found a work-around until they were able to source more black modules. Because there are 2013+ models with the black modules as well. So there are just some random productions with this silver disc-horn.

I'm just curious as to why my alarm is acting up just like those with the leaking battery inside the black alarm module, since mine doesn't have this module whatsoever. Same type of symptoms such as losing key fob range, intermittent no "beep" upon arming, random alarm sounding off (honk-honk-honk) when opening the door using keyless entry (Porsche entry and drive), etc.

Wondering if there is an alarm module elsewhere on the car that I can swap with a new part. Or another place with a leaky Ni-MH battery....

Originally Posted by CS958

It intermittently would not make any sound when arming, the range was going to crap and the alarm would sound when the door was opened with Keyless entry. So I thought it must've been the leaky battery, especially given that it is right about the 10 year mark. So I ordered the latest iteration of the part and even supplied my VIN to 2 Porsche dealerships. They both said it would fit, not mods, no adapters.... just plug and play.

Originally Posted by twodollardoug

Right, so if you have the silver disk then there is no battery or module to replace. Am I understanding this correctly? Can you tell by the sound of the beep if you have one or the other?

Originally Posted by garrett376

It sounds like you are just throwing a part at this without diagnosing it, as your problems actually sound like you have a door latch failing, which they do intermittently at first. Have you checked for faults with an appropriate scanner?