Passat Car Alarm problems

[crone2crone]

Briefly I have had Passat estate for about 3 years now, 2002 model and it has behaved beautifully. however suddenly the car alarm is going off within minutes of locking the doors. I now live in a remote area of Scotland, no where close to a dealer, so have to rely on a local man. He says it is the rain coming through, but I am not sure why it should happen now given there was plenty of heavy rain in Devon where I used to live.

It can't be fitted in any where for 3 weeks, and I am having to leave my car unlocked all the time, is there no way of disabling the alarm so I can lock it without it going off all the time while I am waiting for the repair?

[ghee60]

are you sure its not just the battery in the alarm fob going a bit flat, most alarms will set the alarm off if this is the case to tell you to change the battery

[gramey]

I wouldn't know about the fob battery although that sounds a good place to start. If you are getting water in the car have you kept the drain holes close to the bulkhead clear?
You'll need to remove the plastic trim covering the battery and put your hand in there and clear out any accumulated leaves/debris and then clear the remainder out with a compressor/airline.
A friend of mine who lives in a rural area didn't realise that leaves were building up under there until, he put his car in a car wash and got back in to ankle deep water, eeek! The drains had blocked and the water took the line of least resistance and entered the car through the fresh air vents. I should say this was a Ford Galaxy but the same principle applies.

[paddymm]

If you havent had water in the passenger footwell and judging by the age of the car it might be the alarm battery back up unit. A small black unit 4x3" with the siren built in. Its in the boot behind the side carpet trim and apparently when these start to run down it sets off the alarm. I have just spent a few hours looking for it in a scrappy for my audi A4. The unit is not rechargable and will cost around 80 quid new I hear. Try going to a scrappy and finding a similar car to yours rip out the boot trim and disconnect a replacement. You might get lucky and find one that has been replaced recently or maybe even try a newer version you might get a couple of years out of it. I took out a few alarms a couple of horns and an accelerator peddle 6 items altogether and the scrappy charged me a tenner for the whole lot. (he cant charge more because he couldn't guarantee the alarm unit.....bargain i thought. Try this before going to the dealer who will charge for a diagnostic then parts then labour and i think its worth the 10 pound for a gamble.

[jimbo73]

I had a similar problem and had to leave my car unlocked....

It still seems to happen now in extreme cold conditions, my friend who is a VW mechanic was stumped and so was his colleagues....

It fixed itself after a about 5 days.....

If you find a definite answer please post it, as it may help others (like me) in the fiture...

[guyg]

I think paddymm may be on the right track, I had similar problems, although with the Passat, the sounder is located in the front plenum chamber where it can get wet and subsequently corrode the internal electronics.

http://www.vwaudiforum.co.uk/forum/showthread.php?t=3916

I still haven't replaced it yet...

Cheers

Guy

[Denny57]

Hi All

just to say my alarm seems to go off intermittantly in very cold weather had to leave it unlocked on a few occasions

but up to now I have no solution

Regards

Denny

[cx02149]

Hi, my wife sussed this out. The Alarm on our 2001 2.0i Saloon goes through phases when it bloody well goes off randomly, drives you nuts especially at night. The solution in the manual doesn't work (turn the key in the drivers door lock twice in quick succession to disable the alarm) Instead with the car unlocked open a rear door, go inside and press down the locking button on all the other doors, then press down the button on the door you have open and then close it. It is now locked with the alarm disabled. I tried it initially setting the drivers door tab last but it wouldn't work. (by locking button I mean the little button which pops up when the car is unlocked on each door) Cheers, Tony

[bobaka]

If your battery is over 4 years old you might want to replace it or swap with a newer one to see if it makes a difference. Low output, especially on colder nights, can cause all kinds of random error codes throughout the car. That might be related to wiring connections but if a new battery solves it that's the practical solution.

[Baron_Samedi]

Also, I found that my car's alarm acted erratically because the bonnet sensor got drowned - dried it out and all is fine... for the time being :approve:

So, check that sensors like the bonnet and boot are working okay.

[bobaka]

Yes the switch on the hood/bonnet latch is visible if you remove the plastic shield and look down. I sprayed it clean with silicone lubricant. I had a couple false alarms after replacing door lock module and battery. Now they have stopped. Even with very cold weather today. On www.passatworld.com (http://www.passatworld.com) there is a lot of additional comment about checking ccu, ccu harness and switches on various door/hood/trunk latches.

[TUG]

My alarm was going off so, i cleaned out the bulk head,lifted the carpet and dried it out and still had problems!!!1
finallyg now took it to a vw specalist and they found the problem!!!!!
they said they have never had to replace a ccm and it was the connecters down the left hand side of the kick plate that were corroded!!! all is workin

[bobaka]

I have seen others report the same or similar.. connector/ground/corrosion. My alarm went off by itself again today so that is the next thing I'm going to check. Will report back.

My independent shop guy also said he had never had to replace a CCM when I mentioned it and they work on a lot of VW's and there are at least 4 mechanics in that shop who've been doin it for years.

[stonedagain]

If you have access to Vag Com, it will tell you the last four reasons for the alarm triggering. My passat had three fault codes relating to the alarm siren itself. On removal of the back of the siren, the pcb was found to be badly corroded & the terminals of one of the backup batteries was non-existent.
A replacement siren from the ******** cost me £82.00. This was caused by the usual blocked drains in the plenum, resulting in the siren being submerged in water. Hope this helps.

[bobaka]

It's seems on US models, at least on my 99 made in slovakia alarm horn is in trunk on wheel well. Thanks nevertheless for the suggestion. When I finally get it I will post the result.

[n793]

hi , my keb fob button remote dont work and a alarm specialist cant figure out why it wont work so i have to lock and unlock with key , he has proggrammed new key chip to car but still doesnt seem to work , now soon as i open the door the alarm goes off and hazards flash so i disconnected the alarm horn n drive with the hazards on, wen the car gets to 90*c temp it goes off , seems like something is wet and drying up , i have removed passenger seat and found a connector what goes into a peice of metal and sprayed it with wd40 and alarm still seems to go off . any one got any ideas , im jus totaly lost