Hi Guys, Reaching out for help here... I have a 56 plate Passat 2.0 TDi 140PS with a bit of an electrical gremlin. The alarm keeps going off randomly. it did it a couple of times back in the summer (once when I was driving along... ?!) and i thought it might have been coincidence; b*stard cats or kids or something, but it has become more and more frequent the last week or so, so much so that it is now a serious problem. (resulted in struggling to start this morning) First of all the alarm would sound, now the indicators just seem to flash, this happens when i lock it with the remote and leave it. could be 5 mins, could be an hour into leaving it. I have looked on various forums and websites and lots of people seemed to have a similar problem with the previous Passat model, but not this one. I assume its either water getting in somewhere (which would explain why its only been bad the last week or so) or a wiring or sensor problem. I have checked the battery tray (suggested by others who have experienced this) and there is no water sloshing around, I have checked that all the doors and tailgate lock and unlock correctly and they appear to be fine, I have taken the wheel & arch off and looked at the carefully concealed siren and it doesn't look wet or damaged and I'm at a bit of a loose end. Does anyone have any suggestions on what might be the cause of this before I have to take it to a garage to hook it up to a computer and foot a massive bill? many thanks.
You've probably got water in the alarm siren under the bonnet causing it to shortout. it happened on my mates VW Vento after he got the engine steam cleaned which caused alot of issues. I took cover off siren for him and dryed inside it with blue paper towels and a hair dryer. The water can be from a blocked water drainage pipe which can collect at the wings/ battery tray area.
thanks, but the siren seems to be in some sort of box hidden up in the driver's side wheel arch, its not near any drains to my knowledge or under the bonnet.... no idea how to remove said box either, it appears to be riveted on or something...
Wing will probably have to come off or at least inner wheel arch liner. It sounds like water is getting into the alarm system so how. I think that is the problem IMO.
thanks for your advice, I was afraid it meant taking the wing off! anyone else have any ideas before I resort to this??
I had this on my mk4 in my case it was window washer leaking on the boot lock switch The door lock switch's can play up as well When the alarm go's off check to see if any of the puddle lights are on inside the car Seen this a few times with my 4motion in the damp and cold Could be worth spraying all the locks with wd40
Had a similar problem when I had an Audi a6, and as mentioned earlier, it turned out to be the micro switches in the drivers door lock. Can be repaired, but I opted for a new lock, not cheap, but didn't want to get locked out and stranded!
the locks all appear to function correctly, (as in, they all lock and unlock with the remote) could there still be a problem? i checked last night when the hazards starting flashing, no courtesy lights on.. which only leaves the boot or bonnet. anyone know where the sensors are for these?
the bonnet switch gives trouble on the passats too coming loose from the bonnet catch, I cable tied mine shut so it thinks the bonnet is always closed
Would this not show as 'bonnet open' on the MFD though? I've just opened the bonnet and locked it, the hazards then started flashing around a minute later. think the siren has had it. Does anyone know if the alarm/siren takes its power from the main battery? dor does it have an auxilliary battery?
Ah yes you have MFD. Obviously my bonnet is never open on the MFD. If it flashed but no sound I would suspect siren. had that on a Rover 220 a few years ago.
there is an update... last night on the way home from work, there was a 'ping!' a sort of 's**t what is it now?!' ping from the dashboard, you guys know the one... I glanced down and for a split second it said 'passenger door open' then disappeared. So I suspect, there must be a faulty micro switch in one of the doors, which is occasionally sending a signal to the computer saying that it is open. so the hunt now begins for the faulty door!
I just thought I should post a follow-up to this post in case anyone is thinking 'AAAAAARRRGH mine is doing that!' or something to that effect. after spending lots of time researching, speaking to people in the know and buying door latches and parts, the problem was eventually found to be in the door 'Control Module' which is a black box about 4x2 inches connected to the electric window motor. For whatever reason, it was deciding that the passenger door was open, when clearly it wasn't. This was 'waking up' the car when it was locked, making the car think that it was being broken into. This made the alarm go off and the interior lights come on ,and also was causing a 0.5 amp drain on the battery. a friend in the know with access to VWs computer system said that it was logged as a 'common fault' and the hardware was corrected from late 2007 onwards. Other symptoms (if its the driver's side) can include the boot opening by itself, the fuel cap opening by itself, or windows operating by themselves. FUN AND GAMES VW!!!!!!
same prob on my 2003 passat thought it was siren fault but cannot be the case on mine as the siren is on a shelf in the garage.but sometimes at night i can see my hazzards goin off through my house blinds but dont bother me now as it makes no noise.still would like to rectify it at some point but dont really know what to start with it this must be a big fault with vw ive heard of this loads.
when I was reading up on this, a lot of the previous shaped Passats had this issue and it was down to water in the battery tray. You might want to check that out! also could be the control module that is behind the glove box
The PL35 chassis has that problem, the PQ46 (B6/7/CC) platform has none of these problems with water ingress thank God!. The door control modules are a known bugbear on the B6. UKPassats.co.uk forum is an excellent resource HTH
