False alarm

[simc]

Any ideas why my alarm goes off almost on a daily basis? The car has been into a main dealer for a day and they could find nothing.(They managed to put 85miles on the clock and screw the fuel consumption for a 20mile collection and return, but that's another story). As an experiment, i isolated the ultrasonics, but still got woken up with the neighbours at 3:40am this morning.All doors are secure. Have taken to leaving it unlocked, which is not an insurance situation i am happy with.

[discowill]

I presume you've checked that the air freshener isn't swinging freely!
Sorry couldn't help myself, my alarm in the past has randomly gone off twice in 6 months, for no obvious reason.

Is the car on a incline? Was it windy?

If it persists then take it back to the dealer and demand your money back or a replacement car.

[trix]

there was previously this this & this. anything that could possibly be setting off your internal sensors? are your windows definitely closing & not being obstructed by anything? have you tried turning the internal sensors off for a night & seeing if that cures the problem? (button low down on drivers B pillar that you press before exiting and locking..)

[monkeyman]

Do you leave your car the side of a busyish road? Even a road that has a few lorries/buses traveling up and down it? Ive found in the past that my alarm has gone off a few times when the bin men and other lorries go past. It seams to go off if the lorry engines goes to a certian RPM. Maybe thats the problem?

[simc]

Thanks for the replies, guys. The alarm sounds with the ultrasonics on or off ( and i don't have an air freshener or furry dice). It is parked abour 25 yards from a quiet country road in the village, hence the sound of armageddon when the bloody thing goes off. Goes off on a slope and on the flat, windy or still. Where are the sensors for the doors? The rear hatch is held against spring tension. Could this be making an open/shut connection. Maybe wind lifting the bonnet a fraction?

[scimitar]

Try leaving ventilation on recirculate?
I used to have an old scimitar coupe with straight through exhausts and could set off a whole line of car alarms by flooring it

[ZephyR]

Any connection with rainfall ? Or after washing it the same day.
Is it only at night when this happens?

[simc]

Can't seem to find a pattern. The last few weeks have been bone dry. It goes for days without a problem, then screams 10 minutes after being locked, or, which really p...s me off, waits until the early hours to play up. It is going into the main dealer overnight in a couple of weeks, but i would have thought that, a) the diagnostics could show a problem, and, b) the sensitivity could be adjusted. My wife took it in last time and they just wanted to know if she could shut the door properly!

[Deacon]

Not sure it would be relevant here but I had a similar issue many years ago with an aftermarket fitted alarm. The problem was traced back to the bonnet switch being mounted fractionally too high which on occasion led the alarm to think the bonnet had been opened and so set the alarm off.

Again not sure if it's any help here but maybe it's something bizarre like that?

Deacon

[simc]

Thanks. My instinct is that it is a poorly aligned/adjusted sensor. I get the strong feeling with main dealers, that unless the computer tells them which bit to replace, they are at a bit of a loss. Lets see if i get any joy next week. Will post a cure, if there is one, or just buy some earplugs.

[RW1]

I get the strong feeling with main dealers, that unless the computer tells them which bit to replace, they are at a bit of a loss.

Correct. They won't recover costs from VW under warranty spending loads of time chasing an intermittant fault which they cannot reclaim against. It needs to become a hard fault which may never do unfortunantely.

It probably doesn't register in the diagnostics because the alarm seeing what it belives is a genuine forced entry. Points to a rogue noisey sensor/set to sensitive ultrasonics or a boot - bonnet- doors switch as said above. All can be genuine forced entry to the alarm, but false triggers to the owner.

Just have to be patient with them. At least they are looking at it for you again.

C.

[simc]

Car has been back in on two more occasions. Still has the alarm sounding for no reason, often in the early hours. I sleep with the key by the bed. If anyone were trying to steal it, i would simply roll over and unlock it for them at the first sound of the alam. VW cannot get to the cause. It goes in this week to disable the audible alarm for good. An immobiliser is all you need. Who ever takes any notice of an audible alarm? Got to stop it, or I will be forced out of the village by pyjama clad locals with pitchforks. Otherwise, it's a fantastic car!

[Gilez]

I wouldnt accept having the alarm switches off mate. The alarm is a feature of the car and should be fit for purpose and work without false alarms. As such, tell them they need to find out the problem. Stand your ground with the dealer and tell them to sort it. I would also ring up VW Customer Services and see what they say too. You might also hit future problems with insurance etc....when saying what factory fitted systems there are.

You say you have isolated the internal sensors, so to me that must mean that there is a problem with the alarm unit itself. I am no expert in such things, but logic would tell me it is one or more of the following:-

1. An electrical fault - perhaps the supply to the alarm module is going off and causing the alarm to think it being tampered with.
2. If there are contacts for the doors/bonnet etc... one or more if faulty.
3. A fualt with the alarm module itself.

[simc]

Latest update
Car went in last thursday (4/8) and is still with the dealer. Lots of tech talk about the CPU showing the alarm has been triggered, but not the source of the trigger. Data flowing back and forth between dealer and VW UK.
Should get it back tomorrow. Can't complain at their thoroughness, although i am not sure it's 7 days' work, ( it is always in the compound as i drive past twice a day). They gave me a demonstrator Passat estate bluemotion in grey. Lovely car, but have already lost it twice in car parks. Not quite got the zip of the 'Roc!

[simc]

I:00am. Just been woken by the bloody alarm again (car's open now if anyone wants to nick it). Forgot to say that, although they think the fault has been identified, the part is on" back order", whatever that is. Any idea what that means or how long it takes?

[RW1]

the part is on" back order", whatever that is. Any idea what that means or how long it takes?

It means either VW have no stock generally in Europe or the dealer through the VW(UK) is having to ordered it from Germany. Usually takes 4 days to arrive at the dealers if there is stock in Germany.

If there is no stock available and it has to be made, can take 3 to 6 weeks.

C.

[simc]

Success! Well, sort of. Got a call on the 19th saying the part was in. Left car for the whole week, as i was on holiday. Drove back Saturday 27th to be told it wasn't yet finished. Oh, and by the way, the service department is shut till Tuesday! So they had the part and the car and waited seven days to start work on it. Picked it up Tuesday. Control unit and boot light assembly replaced. Got home, found black scrape marks on the mirror edge and offside front bumper, which polished out, luckily. Went to start the car Wed.......nothing! The other key is no longer functioning due to the changed control unit. They now need car and both keys sometime next week to re- programme. My hassle, my need to arrange lifts, and my bloody diesel going back and forth to the dealer! At least the alarm is fixed, but i note that as of today it has taken an entire registration period to sort. My new car now works, but is no longer new.
To end this thread (tempting fate!), buy a Scirocco, they are superb. Just don't buy one in Kettering.