dreaded intermittent alarm...

[stubbs]

Hi Guys, i've an 02 passat estate that has just inherited the the common fault of an intermittent alarm. It’s gradually got worse over the last couple of days and pressing the fob twice to disable the alarm, now, has no affect.

I'm armed with the useful info from previous threads and a copy of the appropriate Haynes manual... and here is where my dilemma starts. My initial plan of attack is to check the comfort unit in the passenger’s foot well and the Haynes manual states i need to remove the passenger seat and be able to continuously earth the airbag that is integrated into the seat. Is this essential, previous threads suggest it’s a simple thing to do?
I’ve removed the retaining screw on the left of the foot well but nothing gives easily and I’m a bit anxious of causing any damage.

Any advice offered much appreciated.

[kenney]

You do not have to remove the seat.However,i would suggest if, you have diagnostic equipment,in measured value block you can see, what has activated the alarm.

[stubbs]

You do not have to remove the seat.However,i would suggest if, you have diagnostic equipment,in measured value block you can see, what has activated the alarm.

Thanks for the response Kenny, i don’t have any diagnostic equipment unfortunately. I guess this is the only way to find out for definite, my plan was to eliminate all the obvious things that have been discussed in past threads.. check for moisture in the appropriate places, comfort unit door sensors etc.

I just did not feel comfortable with having to remove the seat.

[kenney]

In that case ,why give yourself a lot of maybe unnecessary work, when with the right tool, can pin point the fault.I dont think i have heard of the CCU activating the alarm,without other faults present.Usually it is the door locks or tailgate lock which are the culprits

[stubbs]

Thanks for the advice, Based on what i've read here i'm looking for any water/moisture ingress on the contacts of the sensors. Are the sensors easy to locate on the doors, tailgate locks? The haynes does not seem to highlight them.

[kenney]

The micro switches are not replaceable,on the the door locks,only on the tailgate lock.It is a fairly complicated job but there are those that have,taken the door locks apart and repaired them,

[stubbs]

thanks again, it sounds like a trip to a local garage. cheers

[passing]

I had an intermittent alarm which went away when I cleared the water ingress from the plenum (again). It is worth checking the carpet around the ECU in the passenger footwell. I had nothing showing on my vagcom.

You can easily release the passenger seat two screws and two bolts and by releasing the cable clip carefully, lift the seat up onto the drivers side. This avoids any hassle of disconnecting or earthing the airbags etc. The front quarter trim panel is one more screw and then you can prise the carpet away to look underneath. It takes about 15 mins each way - and a few hours with the hairdryer if you find water.

Yes the ******** quoted me two hours to diagnose the problem - I can drive a hairdryer for less than they can plus my drive is not a 70 mile round trip away !

Anyone know which connector is which on the panel behind the front quarter trim ? I could not find any clue in my haynes manual and assume they go off to the respective control units elsewhere in the car - would be a useful place to isolate problem units quickly for suspected current drain.

[stubbs]

Thanks passing, as you say its certainly worth eliminating before taking out a second mortgage. Interestingly now the weathers dried up over the weekend the alarm seems to have stopped going off randomly. Further investigation required.

[Fourbears]

It'll be wet as thats exactly what my alarms been doing. You really need to check under the carpet which takes about 5 minutes to do. Take off the trim in the footwell, gently prise up the sill trim and pull the carpet up and stick your hand in. If its soaked you've got to dry the carpet, wiring and CCU box. I did it with a hairdryer. Took all yesterday afternoon but its done now.

[richard@thebrae]

Hi, hear is a link to the job in full, :- http://www.headfuzz.co.uk/?q=vw_ccm

Also it could be the backup batts. in the alarm sounder being flooded or just old age. (its in the plenum chamber to the left of the Batt after 2001) or in the boot previous years. This was a problem I experianced but you normally get a chirping sound when you lock the car to warn you that it is on the wain.

[Fourbears]

My alarm is now going off intermittently! In fact its usually an hour after locking it so I've disconnected the siren. My footwell and CCU are dry so whats the problem???

[richard@thebrae]

Hi your previos post about a month ago indicated that you had suffered the dreaded flood under the footwell around the wiring and convenience can.

Have you checked the wiring connections in this area for corrosion ? :- again see this link in full. http://www.headfuzz.co.uk/?q=vw_ccm

Can you not have a scan for the fault log with VAGCom or similar it might save you a lot of grief.
Regards Richard.

[stubbs]

The problem simply went away, i checked the foot well and no moisture detected, as you previously suggested the backup battery could be faulty but i'm not getting any chirping and as the problems disappeared, for now anyway, i'm loath to change anything.

Unfortunately no I’ve not got a vagcom to detect the fault.

I'm pretty convinced its damp/water related though as we were away the weekend in the heavy rain off the coast of Cornwall and when you lock the door using the fob the indicators do not come on to indicate the cars locked and armed. This is what happened when i suffered the problem last time and obviously resulted in the alarm going off randomly. When apparently everything dries out the indicators do blink when the cars locked/armed.

[richard@thebrae]

I would say you definitely have a moisture problem and you need to get into the plenum chamber and do two things :-

1) Check the drain holes, and :-

2) Strip out the Pollen filter and renew the seals, use the dealer elastomer type for the outer seal and the foam one (supplied) for the inner.

You really have to take out the scuttle (rain deflector) and I would have a new one on standby at circa £12. A new pollen filter tray is circa £5 and includes new seals, but I recommend getting the elastoma one off the roll from the dealer.

As a safety precausion check that the door area is not letting in the water 1st before you go into the plenum chamber.

If you need instructions send me a private email address and I will send you a copy in pdf format. also see this link, scroll right through it

http://www.vwaudiforum.co.uk/forum/showthread.php?t=12677
Regards Richard

[Fourbears]

Yep, some of the wires are a little green! I'm going to sort these out when it stops raining so I hope this will cure my problems. Can't get the car under cover unfortunately! Don't know where the water came from, other than through the pollen filter but its bone dry despite the rain!

[richard@thebrae]

Hi the water does not usually come through the pollen filter, but under the pollen filter tray.
The origional seal/gasket (the outer one) is like a closed cell foam, and it rots that why I said use the elastomer one "off the roll "that the dealer uses.
They will give you this in liu of the gasket if you ask.
The inner gasket is open cell foam and I think it only seals the air passage from the filter.
Take a look at the link in my previous post it has photo's
Regards Richard

[Sheepdog]

Sorry but I have just seen this.
Dont know if you still have aproblem, but
Within a yr of getting my car, alarm went funny, as you described.
Went to dealer, dealer very good had a look there and then. Found corrosion in the conections in the Driver footwell, Well thats where they said anyway, But since then had problem with cover over where you put your left foot being loose. Try checking in there.
Fixed mine.
BUT Corrosion in a new car ????

[stubbs]

thanks i'll take a look.

[MalcQV]

Sorry but I have just seen this.
Dont know if you still have aproblem, but
Within a yr of getting my car, alarm went funny, as you described.
Went to dealer, dealer very good had a look there and then. Found corrosion in the conections in the Driver footwell, Well thats where they said anyway, But since then had problem with cover over where you put your left foot being loose. Try checking in there.
Fixed mine.
BUT Corrosion in a new car ????

Rubbish is it not? Very bad design and lets the car down.

[sergiup]

I'll blame water under the carpet too - I had dried most of it out, but some still remained, and for some reason the alarm did exactly the same thing as yours (even though the CCU was totally dry inside the box).

I had the carpet up for 2 weeks, it was still damp...

[Fourbears]

Right sorted the underfloor connections so here goes.................. I also seem to recall that someone said that the boot lock can cause a similar effect. Since mine had a new one last year, when I bought it, could it be this? It was changed by a non VAG garage.

[Fourbears]

Well it seems its all solved!!! Thanks all!