Car alarm going off, and then key remotes forgotten!

[MooLard]

Good morning!


Upsetting times with my otherwise very pleasant 2003 A4 1.9 TDi quattro because it's now the second time I have been told the hazards are flasing on the vehicle and when I go to turn it off or unlock it the car has forgotten my remotes!


My mechanic friend suggested my first port of call would be to check the scuttle panel to ensure no water is entering the passenger footwell. I checked the CCM box and it does look dry as do the wires leading to it.


Next I checked the pollen filter and that is dry as is the plastic housing it sits in. Then I took off the various bits in order to remove the battery, quite heavy when you are trying to lift it with outstretched arms! Then removed the battery tray that it sits on and found the drain grommets, it was all dry down there and the grommets have either been modified so that they are very open or they are of a different type that do not have a normally closed slit in.


Anyhows, it doesn't seem like water ingress, I've checked for fault codes and the auto-scan hasn't pulled any up, can anyone suggest what to try next? Does a faulty alarm (it doesn't sound when the hazards were flashing) or dead alarm battery cause this issue to?


Here's hoping someone can help.

 

[quattrojames]

Check the siren in the offside of the boot area near the avant. I expect the batteries have leaked and fried the PCB.

Check one of my recent threads where it happened to me. I can't post the link as the forum is dodgy etc...

 

[MooLard]

Morning James

Many thanks for the quick response, did your car have the same symptoms as mine then? Alarm going off and forgetting the key fobs?
I think this is my next port of call to check, will save it for the weekend though because working in the wet under cover of darkness last night is not the preference!

 

[Mike.M]

As James says it sounds like a failed siren confusing the crap out the car.

In the saloon it is in the boot far right and down, so the trim panel has to be removed.......unsure about the avant.

 

[MooLard]

Morning Mike, good stuff in the Avant I'm pretty sure the tiny sub-woofer housing is in the way so it's a few bits to remove to access the alarm. Is there any adverse affects to just disconnecting it for a few days? I'll probably experiment anyway.

 

[quattrojames]

I ran mine for months with no siren, it was fine.

 

[DieselJake]

Mine had no siren which I thought was all good until I go to a house party and some d*cks there think it would be a good idea to jump on the car.

 

[MooLard]

Evening! So I got access to and removed my alarm siren box yesterday, and found some old batteries inside where one of which had leaked a bit. I intend to replace those with a digital camera battery, something that is 7.2 volts and of the ni-mh type so as to replicate what is already in there, it'll probably have it's own case anyway, which will keep the contents safe from the PCB in the future.
There's no point in me doing this until I solve and replace the fried component, can anyone tell what it is? Long shot I know, but I hope someone can help.

 

[PetrolDave]

There's no point in me doing this until I solve and replace the fried component, can anyone tell what it is? Long shot I know, but I hope someone can help.

Really hard to tell, but it looks like there's a legend to the left of it saying C?? which implies a capacitor, and from the size of the pads it could be some kind of tantalum or electrolytic - but it's really too hard to be sure of any of that. What you really need is a picture of an undamaged board - but even that may not tell you the value (as only large value surface mount capacitors have the value printed on them).

 

[Markinoxon]

Moolard, any luck with this? I have the same issue with my cabriolet.

 

[MooLard]

Afraid not dude, I've parked the issue for now but wouldn't mind getting a working alarm from Germany or something and fitting it with a new external battery, it would in theory stop acid from getting on the pcb again

 

[Markinoxon]

Mine has come back to life! I had the front passenger side carpet up for a week with the heater blasting under it whenever I used it, bought and used a half cover from Hamilton Classics, had a £50 dehumidifier from b&q running in the car over night and parked it under cover at work. Eventually I gave up and decided to put the carpet and trim back but gave the convenience ECU thing under the carpet a good blast with a hair dryer first. I gave the key reset procedure one last go and to my amazement the car 'klunked' when I pressed key...all sorted.