Alarm going off when I lock car - what gives?

**sejman** · 02-24-2010 09:50 AM

This has gone from randomly occurring to every time now - I cannot lock my car now without the feeble alarm beeping going off. Worse - it doesn't stop when I hit the unlock button on the remote or put the key in and unlock the car. It seems to eventually time-out while I'm fumbling around trying to get it to stop.

There is no indication that any doors/trunk are open on the dash. I've tried disabling the motion/tilt sensors with those switches by the trunk release. Nothing helps. What am I missing here?

**nurburgracer** · 02-24-2010 10:59 AM

Does your car have the tow/elevation switch?

**sejman** · 02-24-2010 11:14 AM

It has two switches adjacent to the trunk release switch - doesn't seem to matter if I activate them or not (my understanding is that when I click them and red LED lights up that means that the relevant alarm sensor is deactivated...right?).

**DynamicDrew** · 02-24-2010 12:08 PM

It could possibly be a faulty door latch. The electronics inside the switch can go bad and cause the alarm to go off at "inappropriate" times.

**sejman** · 02-24-2010 12:32 PM

But wouldn't that show up as a "door ajar" warning? All doors, trunk lid, etc. seem to be good when I go to activate the alarm.

**DynamicDrew** · 02-24-2010 12:49 PM

No not necessarily. Symptoms of a faulty door latch can manifest themselves in very strange ways. We just replaced a door latch in a 2004 Allroad because the poor guy kept having his keys locked in the car, with the key in the ignition. The car thought the key was out of the car and that the lock should be engaged so it locked itself, even though he did not try to lock it at all...the poor guy thought his car was possessed.

Another symptom is if the alarm goes off when trying to start the car, along with the symptom you are experiencing. The door ajar warning is just yet another symptom but you can have all or only 1 of these symptoms with a faulty door latch. Tricky little devils they are...

**sejman** · 02-24-2010 12:54 PM

Hmmm...never had the alarm go off while starting or driving the car. Does a diagnostic scan show this problem and the location, or is it a trial and error thing to track down?

**DynamicDrew** · 02-24-2010 01:03 PM

Unfortunately, a diagnostic scan generally will not help in this situation because the door latches are not tied into the OBD system. This is a factory alarm in the car correct?

**sejman** · 02-24-2010 01:05 PM

Right - factory alarm. At this point, I'd be happy just disabling the alarm so that I can lock the car...

**dangerouslaser** · 02-24-2010 01:13 PM

has your keyfob gotten wet? have you tried another keyfob or locking the doors physically with the key and see if that causes the alarm to go off too? maybe a short in the keyfob is causing the panic button to go off when you click the lock button?

**sejman** · 02-24-2010 01:29 PM

I've only got the one keyfob, but it does the same thing whether I lock using the keyfob or physically put the key in the door. Interesting idea on the panic button, but I think this rules this idea out. To be sure, I'll test the panic button and make sure it operates and causes the same behavior.

**AvantJunkie** · 02-24-2010 03:29 PM

Originally Posted by DynamicDrew

It could possibly be a faulty door latch. The electronics inside the switch can go bad and cause the alarm to go off at "inappropriate" times.

I agree with this. I had the "phantom alarm" problem with my old B5. There was never an indication of a door being open, but after exhausting all other options, I started checking the door switches just for the hell of it. It turns out my rear passenger door switch wiring was loose, which was causing the alarm to go off. I didn't even need to replace it, just resituate the wiring. Hopefully you figure this out, because I know how annoying it is!

**Mani** · 02-24-2010 04:07 PM

Guys,
I have the same problem. My dealership diagnosed and identified a faulty passenger side door latch causing the alarm to go off frequently... quote to fix this was little more than $550. I declined it ....

does it happen to you every single time you lock using remote or occasionally?

**n7plus1** · 02-24-2010 04:30 PM

you sure its not the "interior alarm"? is the car empty or have passengers?

**Mani** · 02-25-2010 10:00 AM

Originally Posted by n7plus1

you sure its not the "interior alarm"? is the car empty or have passengers?

In my case it is always empty car... no passengers inside... the alarm goes off once in a while when I lock the car using remote...

**joebleu** · 02-25-2010 10:52 AM

If you want to disable/remove the alarm, this thread will help:
http://www.audizine.com/forum/showthread.php?t=306320

**n7plus1** · 02-25-2010 11:23 AM

haha, thanks for posting my diy...forgot i wrote that up.

**218army** · 06-24-2010 12:24 PM

I am having this exact same problem except it only goes off when I lock the doors. Also, its not the full alarm with the lights flashing and everything, just the beep, beep, beep from the trunk speaker. Oddly enough, it only happens every third time I lock or unlock the doors. I never though that it might be the door switches, but I will check those out and see if thats the problem. Did you guys ever solve this problem?

THX

**sejman** · 06-28-2010 06:59 AM

I never solved this one - it is really seems like some kind of intermittent switch/connection issue. Lately, it has been locking "quietly" on the second attempt. Like yours, mine doesn't flash the lights - just the beeping from the trunk speaker.

**jetflyr** · 08-12-2011 07:04 AM

I know this is an old thread but my car has been doing this since I replaced my radio. I guess it's the alarm ground to the stock radio. I've heard of something tripping in the stock head unit causing this though I believe VAG-COM came up with something...

**R3V3NANT** · 08-12-2011 07:44 AM

I have had the same problem since I got my car. My only recourse was to lock, wait one second (right as the tail/side marker lights begin to flash), then press unlock and then quickly lock again. It works every time. I will investigate the door wiring though!

**kwimberly** · 08-12-2011 08:09 AM

Weird that this thread was just bumped. Last night my trunk siren started going off on its own. It would beep a bunch of times, then stop. It wouldn't stop via the key fob or if I opened the doors. It would do it every few minutes. I read the couple of threads that discuss changing the corroded batteries or otherwise replacing the unit. I noticed that I have ants along the drivers side door sill. I wonder if they messed up a sensor?

I have multiple codes saying that: data bus for comfort system has single-wire operation, the alarm was triggered via the tilt sensor, no communication with the alarm horn, and the door control module for all 4 doors says single-wire operation.

I would think that if ants are messing with one sensor, then I wouldn't have gotten all of those codes. I ended up pulling the plug from the siren after I pulled and cleared the codes. Maybe I'll buy a new one.

**Tgr_Clw** · 08-12-2011 08:23 AM

You can add me to this exclusive club. Been living with this problem for the past 1.5 years or so.

**kwimberly** · 08-12-2011 08:31 AM

Originally Posted by Tgr_Clw

You can add me to this exclusive club. Been living with this problem for the past 1.5 years or so.

The random beeping? I know that 4 beeps means the batteries are getting low, but mine was beeping 20 or 30 times in a row. I was worried my neighbors were going to complain if it happened all night, so that's why I pulled the plug. It was either that or leave the car unlocked.

**falkor923** · 08-19-2011 05:28 AM

You guys are lucky. I have had the problem for 3.5 yrs. I noticed certain ambient temperatures make mine worse! It all began when I was backing out of the driveway at an angle and noticed my interior cabin lights fading on and off. After a few weeks, that interior light would come on with hard acceleration and go out off throttle. (apr 91 chip) Lately, it has not been a problem, but I know come winter or something it will come back. I bought a lock module/pump used. My car had the exact same symptoms as before. When it starts to wig out, I don't get the trunk "honk" when I lock with remote. Sometimes lights would flash with no audible alarm, sometimes I would get a full panic, passenger footwell courtesy light and dome lights are constantly on now. PITA man. I have VAG but cant figure out how to read the last alarm trigger. I just finished stage 3 a week ago. Interior light switch it switched off using button because it will be constant on if left in automatic mode. Passenger footwell lights are still on. About a year ago, it would indicate driver door open...sometimes...while driving I would have the chime going off until it timed out. I would get a driver door open symbol on dash.....sometimes. Makes me think driver door, but how do you "check" a door switch ??

All of my symptoms were intermittent which is why I bought the lock module.

**DCisdifferent** · 08-24-2011 12:40 PM

Mine's been doing this for a few months now. It's odd, it's only when I get home from work that it does this, so every other time this happens. Starting to really irritate me..

**thecheda** · 08-25-2011 03:16 PM

My solution was to turn off the alarm chirp that goes off when you lock your car. I cannot recall the value my friend changed in VAGCOM to turn it off. The alarm is still operational (red light will blink when alarmed). Solved the issue of the alarm going off after alarming.

I will check with said friend and post on this thread.

**A4Dit** · 08-25-2011 07:05 PM

Mine has been doing this for a little while too. I just pulled the fuse to the alarm so that I can lock the car.

**kwimberly** · 09-24-2011 06:25 AM

Bumping this to post my codes. I might start new thread if I can't find anything else via searching.

Anyway - symptom was that my alarm started randomly going off. It would beep a bunch of times then stop. Then start beeping again 5 or 10 minutes later. When it first started happening, I seem to remember spotting some fire ants walking around the driver's side door sill. I wonder if they got into some wiring? But would that affect all doors? There has to be something central to check first.

I'm getting these codes. As soon as I clear them, they pop right back. Temporary solution is just unplugging the connector from the siren.

01336 - Data Bus for Comfort System
80-00 - Single-Wire Operation

01134 - Alarm Horn (H12)
49-00 - No Communications

01331 - Door Control Module: Driver Side (J386)
80-00 - Single-Wire Operation

01332 - Door Control Module: Passenger Side (J387)
80-00 - Single-Wire Operation

01333 - Door Control Module: Rear Left (J388)
80-00 - Single-Wire Operation

01334 - Door Control Module: Rear Right (J398)
80-00 - Single-Wire Operation

**A4_Mike** · 09-24-2011 12:26 PM

Originally Posted by A4Dit

Mine has been doing this for a little while too. I just pulled the fuse to the alarm so that I can lock the car.

My car started doing this about 2 weeks ago. I doubt it's coincidence, but I replaced my rear passenger's widow regulator shortly before all of this craziness started. I rechecked that particular door and it seems like the door locking mechanism (to the chassis, not the door handle) isn't being tensioned fully when the door is closed.

Another quirky thing I've noticed is that the driver's side door red alarm light stays lit when locking and the car does not chirp when locking.

I don't have a VAG-COM, but I'm not getting any codes using a Autel MaxiScan MS300.

Which fuse is for the alarm? I simply don't have the time at the moment to mess around with the car and I hate not locking the doors since the alarm randomly goes off.

**A4Dit** · 09-24-2011 07:24 PM

^ I forget the fuse number, check your manual and it will tell you. Unfortunately it is the same fuse that runs your dome and reading lights so you lose them but I like having the peace of mind that my car will still be in my driveway in the morning.

**A4_Mike** · 09-25-2011 11:39 AM

Originally Posted by A4Dit

^ I forget the fuse number, check your manual and it will tell you. Unfortunately it is the same fuse that runs your dome and reading lights so you lose them but I like having the peace of mind that my car will still be in my driveway in the morning.

My manual states that fuse No. 38 - Central electric, anti-theft alarm system, rear lid/trunk release. Is that the right one?

**A4Dit** · 09-25-2011 11:44 AM

Yep, thats it.

**A4_Mike** · 09-25-2011 04:37 PM

Originally Posted by A4Dit

Yep, thats it.

Thanks for the help. I pulled the fuse earlier today and so far so good. The dome / reading lights went out immediately upon pulling it and the alarm hasn't gone off this entire time. That gives me the time to hold off on this project for a bit so I can continue to focus on school. Thanks again!

**samagathos** · 10-13-2011 07:30 AM

Ok, it looks like my first post will be to resurrect an old thread. I've been having a problem with my car alarm going off after I shut off the ignition. It's not too bad to deal with since the key is in hand and it responds to the remote. It is however really annoying to deal with to get out and get groceries. Could this be an issue with an easy fix?

**Tre'** · 12-01-2011 09:34 AM

Bumping this because I have the same problem. I took my siren out and cut it open but the batteries and connections look pretty good. My issue was the siren and flashers would kick on radomly when I got out of the car and locked it. After I took the siren out I had no issues for a couple of days. Siren is still out but now the flashers have started going randomly again when I lock the car. Pulled the #38 fuse but it's still happening. Is there any way to disable the alarm completely or at least the flashing lights but still have them work as signals when I'm driving. I can do without the alarm as long as I can lock the car.

**Pete4 1.8t** · 12-01-2011 11:36 AM

Originally Posted by Tre'

Bumping this because I have the same problem. I took my siren out and cut it open but the batteries and connections look pretty good. My issue was the siren and flashers would kick on radomly when I got out of the car and locked it. After I took the siren out I had no issues for a couple of days. Siren is still out but now the flashers have started going randomly again when I lock the car. Pulled the #38 fuse but it's still happening. Is there any way to disable the alarm completely or at least the flashing lights but still have them work as signals when I'm driving. I can do without the alarm as long as I can lock the car.

In your case I doubt it is the siren that was going bad. I just replaced mine because it would beep upon locking but never flash any lights, the beeping is the only thing that the siren does. You might want to check your door catches to see if one is lose, do the lights inside ever come on or the door open indicator? If yours is a 2002 model you also should have the interior motion sensor, in the drivers side map pockets you can flip the switches so the little lights come on disabling that feature of the alarm and see if it stops it from going off. If it still keeps going off it might be your comfort control module going bad.