A4 B6 Alarm Siren trouble

[ScottNH]

Recently the alarm siren on my B6 sedan started acting up. After I lock/alarm the car, I get the "chirp," and then the alarm starts beeping and doesn't want to stop. Here's what's happening:



Based on reading here, I thought the problem was the battery in the alarm siren, so I replaced the siren unit with a new one. Same problem.

Sometimes I can cycle the fob to lock/unlock/lock, etc. and get it to stop. Sometimes I can get it to stop by putting the key in the door and cycling the alarm.

Any ideas what I'm looking at here? Starting to drive me slightly crazy.

Thanks for the help.

[Luxus Panzer]

Battery. Just unplug the alarm until you find a replacement, or if the alarm PCB is not burnt you can swap in a new battery.

http://www.audizine.com/forum/showth...1#post12049520

[KHARDa4]

I would unplug it also, when those batteries start to deteriorate they leak acid onto the circuit board making it pretty much useless and causing weird issues just like you're getting. Eventually the h12 alarm horn stopped working all together. I would say unplug it now because it can short out getting into the connector then your cutting and splicing, not hateful to do but the down time of ordering a connector and wires to splice from the dealership can possibly be avoided now.

[ScottNH]

Battery. Just unplug the alarm until you find a replacement, or if the alarm PCB is not burnt you can swap in a new battery.

http://www.audizine.com/forum/showth...1#post12049520

That was my first thought, but I just replaced the siren unit with a new one. The video is from after I replaced the unit.

[KHARDa4]

Pull back the harness and look at the wires as well as down into the connector.

[KHARDa4]

It's possible the new siren is having the same deterioration as the previous unit. Was this purchased used?

[Kevin C]

Pull back the harness and look at the wires as well as down into the connector.

Good advice. When the batteries leaked on my unit they leaked badly enough to corrode the connector pins.

[ScottNH]

Pull back the harness and look at the wires as well as down into the connector.

I took a good look at the connections when I replaced the unit. All looked good. No signs of battery leakage on the unit or the wiring.

I have access to another unit (known good), so I'll swap again and report back.

Irritating as all get out.

[KHARDa4]

You wont see it from the outside of the case, you would see corrosion down on the terminals of the alarm horn. If the old one damaged the connector it could be shorting the new one out.

[EuroxS4]

I agree to check the connector internally also peel back the rubber boot and look at the terminals from the other side.Mine were shot.The board was toast.If that all turns out fine.Check for water in the ccm or scan for faults.I've seen bad wiring at the door hinges do this on b6 cars all the time.The wiring for the door normally brakes in the hinge point.This is a common issue on these cars.

[john_gonzo]

Battery. Just unplug the alarm until you find a replacement, or if the alarm PCB is not burnt you can swap in a new battery.

http://www.audizine.com/forum/showth...1#post12049520

I too did the remote battery. Pics here: Alarm-Beep-Stop-Working-DIY-Fix. Probably overkill for most owners.

[khancept94]

i just got done peeling back the trunk liner to unplug the thing today. It was at the point where itd sound every single time i locked the car. Also heard faulty wiring to door latches/ trunk and hood latch may be the culprit. The siren looked in good condition besides the dust collected in that compartment. No signs of corrosion or anything. Just a temporary fix until i can get the system scanned :) no more people staring at me in parking lots when i lock my car haha


Sent from my iPhone using Audizine

[ScottNH]

i just got done peeling back the trunk liner to unplug the thing today. It was at the point where itd sound every single time i locked the car. Also heard faulty wiring to door latches/ trunk and hood latch may be the culprit. The siren looked in good condition besides the dust collected in that compartment. No signs of corrosion or anything. Just a temporary fix until i can get the system scanned :) no more people staring at me in parking lots when i lock my car haha

Sent from my iPhone using Audizine

I'm pretty close to that point (disconnect) myself. Examination of the connector leads and the siren connectors reveals no signs of corrosion or leakage. I'm going to check it later this week with a known-good unit (from my other A4, hence the delay) and see. I'll also scan tonight and see if that reveals any good info.

[Rubba]

Remove and put back the fuse

[SJorge3442]

You cant see if the batteries are leaking without cutting open the unit. I bet you have another unit with a similar issue as your first one.

[badger.]

Also heard faulty wiring to door latches/ trunk and hood latch may be the culprit. The siren looked in good condition besides the dust collected in that compartment. No signs of corrosion or anything. Just a temporary fix until i can get the system scanned :) no more people staring at me in parking lots when i lock my car haha

Few months back my alarm started randomly going off. The hood latch sensor wires were severely deteriorated and were the cause. The "hood open" icon wasn't displayed or anything. I just unplugged and removed the entire thing, and issue was resolved. Note, if you unplug it, if your low oil light comes on you will need to jumper across the wiring again to trick the car into thinking you opened the hood and topped up the oil otherwise the icon won't go away :)

[Luxus Panzer]

YOU MUST IOPEN THE UNIT.

IT MUSR BE CUT OPEN.

THEN YOU WIL SEE THE PROBLEM (99%)

Hope I/we have been clear enough. Good luck

- - - Updated - - -

YOU MUST OPEN THE UNIT.

IT MUSR BE CUT OPEN.

THEN YOU WIL SEE THE PROBLEM (99%)

Hope I/we have been clear enough. Good luck

[ScottNH]

YOU MUST IOPEN THE UNIT.

IT MUSR BE CUT OPEN.

THEN YOU WIL SEE THE PROBLEM (99%)

Hope I/we have been clear enough. Good luck

- - - Updated - - -

YOU MUST OPEN THE UNIT.

IT MUSR BE CUT OPEN.

THEN YOU WIL SEE THE PROBLEM (99%)

Hope I/we have been clear enough. Good luck

Is that directed at me? Because I'm not opening anything. I'm replacing the unit.

O-level maintenance all the way for me.

I just have to wait for the unit.

[Luxus Panzer]

Is that directed at me? Because I'm not opening anything. I'm replacing the unit.

O-level maintenance all the way for me.

I just have to wait for the unit.

If $$ is no obstacle, you have the correct course of action.

[ScottNH]

If $$ is no obstacle, you have the correct course of action.

Haha. If $$ was no obstacle, I'd just buy a new car when something like this happened.

But, for $35 shipped for the part, I'll replace it, and I'm happy to report the problem solved. Seems like my first replacement siren was defective. Back to "chirp" with no "after-chirping."