Roomster Siren sounds for no reason!

[Hippopotamus]

We have a persistent alarm fault with our Roomster  that has bothered us for the whole time we have owned the car. The car is still under warranty but would really appreciate some advice if anyone has had similar experiences.  

 

Car is 13 plate, brought from Skoda dealer last year as used approved. Siren sounds, but does not flash hazards or log going off.  (We brought a webcam to record this)

 

 

Local Dealer have had car a few times and have been helpful (although my wife who mainly uses the car is really annoyed.)

 

Here is what local dealer have done:-

 

Visit 1: 26/04/18 Checked for any stored fault codes using guided fault finding, found that no relevant codes were logged. The vehicle stores the last 4 triggers and also the alarm type. When queried it showed that the car was fully locked and that the Ultra Sonics were responsible for the last 4 triggers. Given the lack of any stored electrical fault we decided to lower the ultra Sonic sensitivity by 50% in case an out side influence was triggering them. We then set our own alarm trigger so we could clearly see what triggers the alarm should the problem reoccur. We left the vehicle in the workshop overnight and in the morning rechecked the list of triggers and concluded it had not activated overnight.

 

Visit 2: 24/05/18 Checked for any stored fault codes using guided fault finding, found that no relevant codes were logged. Locked the car for an extended period and again confirmed that during the testing time no faults or triggers had logged.

 

Visit 3: 09/07/18 Checked for any stored fault code using guided fault finding, found that no relevant codes were logged, however it was determined that 1 trigger was present, again for Ultra Sonics. Due to lack of supporting evidence we were unable to go ahead and replace the Ultra Sonics. We left the car in the workshop for testing from 10am Monday until 10am Friday, the alarm never sounded and no extra triggers were logged. We then left the car outside from 3pm Friday until 2pm Tuesday. When checked again the car still showed no triggers and we did not hear any alarm in this time. It was concluded that this may have been due to outside influences and may not be relevant to the on going complaint. The customer at this point had reported far more than 1 trigger. At customers request we disconnected the Ultra Sonics and returned the car.

 

Visit 4: 29/08/18 Customer provided extra detail when dropping off, we were informed that when the alarm sounds the hazard lights do not flash. This information along with the latest guided fault finding logs (again showing now faults and no triggers) was forwarded to the VW Group Technical Team via a DISS report, we were advised to replace the on board power supply control unit that contains the alarm system. We replaced this, reconnected the ultra Sonics. Locked the car for an extended period and again confirmed that during the testing time no faults or triggers had logged. Believing the car to now be fixed due to the Technical Teams advice, it was returned to the customer.

 

Visit 5: 03/10/18 Customer informs us that the fault still persists as before, the siren sounds and no lights flash. Carried out guided fault finding and this time the 1st electronic fault was logged, a sporadic electrical fault was showing with the alarm siren unit, we replaced the unit and as with all previous visits we left the car locked for testing purposes, both inside and outside. We checked for any triggers or further electrical faults and confirmed again that nothing was logged. 

 

Visit 6: 22/10/18 Car returned to workshop to have a washer hose repair, whilst in we checked the alarm sources and fault memory and confirmed them to still be clear. Car returned to customer and at time off writing, no further alarm activations have been reported since visit 5.

 

 

Since the last visit, alarm did not sound for 3 weeks, we thought garage had cracked it, but it went off twice this weekend both at around 0300-0400am!!!

 

 

Any ideas?

[Kenny R]

I have read on other models sections that the back up battery for the alarm siren only lasts 4-5 years and causes the alarm to sound spuriously when it’s failing.

[Ootohere]

When the Roomster & Fabia and maybe other Skoda had a 'Service Book'  it even showed the Alarm Siren as a Service Item to replace at the 5 year service.

That was then counted as a 'Major Service'.  

Loads have obviously lasted over 5 years and some have not.  But then how cars are used are bound to count.  opening, closing, setting alarm many times. 

or is it using less that uses up the power.

Skoda / VW must have taken a punt at a guess at some point.

 

Then the is the door loom issue, broken connection issue, or bonnet catch, lots to have the alarm going off.

[PetrolDave]

59 minutes ago, Kenny R said:

I have read on other models sections that the back up battery for the alarm siren only lasts 4-5 years and causes the alarm to sound spuriously when it’s failing.

Officially the siren then has to be replaced, but some owners have opened up the siren and replaced the batteries - which is much cheaper.

[bombheads12]

If you know where to get the batteries from please let me know!

I contacted Varta who make the batteries and they say (both Automotive and Commercial) " we do not supply or make these Batteries ummm

 

[langers2k]

14 minutes ago, bombheads12 said:

If you know where to get the batteries from please let me know!

I contacted Varta who make the batteries and they say (both Automotive and Commercial) " we do not supply or make these Batteries ummm

 

 

You might want to add some detail as nobody has mentioned what battery size you're looking for.

 

Still, this thread in the Octavia section might help:

 

I also posted a link for a Varta battery here:

 

[bombheads12]

Aha not all batteries are the same me thinks mine are these, hence the reason i contacted Varta two sets of batteries. And they reckon its a service item to replace the alarm every 5 years??? 

 

[langers2k]

Skoda/VAG expect the alarm siren to last a minimum of 5 years, the actual life will depend how the car has been used. If the battery does die, you'll get a fault code and they'd replace the entire until as it's not user serviceable.

 

Still, looks like they used to be available: https://www.dhgate.com/store/product/original-germany-imported-varta-2x3-v150h/386141500.html

 

You could probably fit two of these: https://www.amazon.co.uk/Varta-industrial-battery-140mAh-Battery/dp/B00C2PEQR4

 

edit:

This looks to match, no idea how much or if they ship to the UK:

https://www.lh.pe/2x3v150h-8pin-battery-varta-2x3v150h-140mah-nimh-recharg-p-5173.html

 

Edited 7 January, 2019 by langers2k

[RichardatWakefield]

Replying to the OP, a couple of years ago, I was getting random alarm siren goings-off on my Roomster, (mostly at night), turned out to be a faulty cabin interior lights switch, when this made contact, the alarm system sensed a tiny voltage drop and triggered the alarm, as this drop would suggest to the electronics that a door had been opened.

Is it also possible that the poor quality glovebox light switches (which tend to drain your main battery) could trigger the alarm system??

[Hippopotamus]

1 hour ago, RichardatWakefield said:

Replying to the OP, a couple of years ago, I was getting random alarm siren goings-off on my Roomster, (mostly at night), turned out to be a faulty cabin interior lights switch, when this made contact, the alarm system sensed a tiny voltage drop and triggered the alarm, as this drop would suggest to the electronics that a door had been opened.

Is it also possible that the poor quality glovebox light switches (which tend to drain your main battery) could trigger the alarm system??

 

 

Certainly worth looking into, I will look at the rigging of the glove compartment micro switch tomorrow.

 

thanks for suggestion

[RichardatWakefield]

I replaced the faulty interior lights switch.

And have removed the glovebox light bulb, it's sitting in the gearlever gaiter.  There's a recent thread somewhere here about this problem.

[Skoda_newby]

Hello all,

This is a great read, considering my alarm has just died. Following this post, I decided to buy the battery and give the battery replacement trick a go. Thanks for the info. I went for the new version of the Varta Mempac cell 3/V150HT.

 

The story also appears here:

 

https://www.a2oc.net/community/index.php?threads/siren-backup-battery-replacement.35824/

 

So, I'll try it out this weekend. If it goes to pot because of a corroded PCB, I'll buy another old one to try the process again. I don't see the point in buying a new one, as I don't know how long they have sat on the shelves for (and they come from Australia), nor will I trust a second hand one because they are normally well over 10 years old. As mentioned, I'd only get one to cannibalise.

[sparky2]

I have been getting false alarms lately so I removed the siren unit on our Scout (2010) 1K8 951 605 cut it open and found the battery Varta 6v 200ma 5/V200H to be 6.7v  with no corrosion so that looks OK, the PCB was also OK so I have resealed with some 'trade seal TP40' and reinstalled it on the car  today. Is there a way of interrogating the alarm to find out what's triggered it ? VCDS showed 01134 alarm horn (h12)  cheers Stuart

[Skoda_newby]

Sparky, not sure about your issue, but the cells don't have to look corroded for them to be past it. It's likely they aren't holding charge at all.

Anyway, I went out a bought 2 new batteries and then set about opening up my siren. My story was different, as the PCB looked decidedly dead. Pictures to follow.

I bought another one off eBay and will install the new batteries when I open it up tomorrow.

What is 'trade seal TP40'?

 

[sparky2]

Trade seal tp40 is like silicon sealant but it's used on caravans and doesn't give off acetic acid (vinegar) like silicon so it hopefully won't attack the PCB ! I put vagcom on the car today and went into measuring blocks and took pics of alarm settings so I will see if I can find something. Cheers Stuart

[Skoda_newby]

OK, so my second alarm unit turned up a few weeks ago and this past weekend I tackled repair #2. The battery tabs were a bit corroded, so I risked it and removed the old battery and soldered the new ones in. That's were things went wrong. The PCB must've had a corroded portion as the batteries and PCB then proceeded to get rather hot. I removed the new batteries and then decided to swallow a bitter pill and ordered a new one via the wonderful discount opportunity we have here at Briskoda. All up price is ~£124.

 

I could have ordered another second-hand one but who knows how many I could've opened up to get the same result? I'm worried I've damaged my new batteries as well.

 

This is one I will put down to experience. If I keep the car past 5 years I will check the condition of the alarm during MOT or service time and as soon as things get a bit dodgy, I can replace the batteries. At least I'll know I have a good PCB.