Alarm Faults

[Bladder1985]

Hi peeps. I have a 2007 A4 Avant S-Line that seems to be possessed. So not long after we bought the car, the alarm would go off anytime it felt like it when it was locked. There’s no pattern to it and there’s no reason for it to happen. I have trawled the internet and forums to find a possible explanation for it. I’ve tried everything including splitting the siren box and replacing the battery. I have recently exhausted all my options so decided to take it to the main stealer. Paid my £60 for a diagnostic and this is what came back. Just like to point out that I told the service guy that I had split the siren box and replaced the battery as it was a bit dodgy. So they had it for the day and their response at the end was;
a) I needed a new siren box because the one on the car had been tampered with and it was supposed to be a sealed unit (I know! It was me).
b) They couldn’t diagnose the fault so wanted to spend another 2 hours chasing it at a cost of £397 to me….I politely told them where to go.
c) they did however send me a lovely little video which shows all the faults to do with the alarm system. Just wondering if anyone has any ideas about the following?
So here goes

1134 49 Alarm Horn (No communication - intermittent (probably because I disconnected it to stop it annoying the neighbours)

1370 35 Alarm triggered by interior monitoring (static)
962 35 Alarm through inclination sensor (static)
1369 35 Alarm triggered by bonnet switch (static)
1371 35 Alarm triggered by door contact switch on drivers side (static)
1384 35 Alarm triggered by glass breakage sensors (static)
1403 36 Rear glass breakage sensors (Open circuit - Intermittent)

So, to me that says the rear glass breakage sensors are at fault. Am I right in thinking they’re part of the heating element on the rear window?

Sorry for the long schpiel but thought I’d give as much information as possible.

TIA, Ian

 

[NHN]

Clear errors, rescan.

Generally once siren breaks it's toast, it leaks, PCB gets damaged, in all cases I got new one, don't even bother wasting time on the battery route.

They suffer from module issues, but without working on the car, couldn't say 100%.

 

[Bladder1985]

Clear errors, rescan.

Generally once siren breaks it's toast, it leaks, PCB gets damaged, in all cases I got new one, don't even bother wasting time on the battery route.

They suffer from module issues, but without working on the car, couldn't say 100%.

There’s no issue with the siren….that deffo works, well it did till I unplugged it. I think that’s what the intermittent fault is, me unplugging it. Is the module something that can be replace easy….ish??

 

[Darashen]

My b6 cabriolet had the same issue with similar codes. I also split the siren box with thoughts of putting in a new battery. In the end I bought a second hand siren off ebay and its behaved perfectly since, no random alarm triggers but it goes off when it should.

Worth noting the same siren box is also used in the Seat Exeo and they tend to be cheaper second hand than Audi sirens.

 

[opinaca]

Same problem here with the siren leaking battery acid...plus the connector got corroded too.....Intermitent no communication fault.
Cleaned everything, changed the battery with an external one with wires.
But now have the same problem again....maybe its the connector.
Gonna buy a new one....