Menu toggle

981 alarm going off

BoxsterLL11

BoxsterLL11

PCGB Member
Member
I have a 2012 981 and just recently the alarm has started going off within a short period of me locking the car.
I have had a quick check round and cannot find anything obvious.
Then the other night I put the car in the garage and set the alarm just to check if it went off again and I noticed the tail lights where on and hey presto the alarm went off.
I keep the lights on auto so I switched the lights off, locked the car - no alarm.
So I was thinking perhaps the light sensor that switches the lights on/off on auto was faulty but the ignition is obviously off when I lock the car so why would it switch the lights on and would the lights being on set the alarm off.
I am puzzled.
Anyone have an ideas or similar experiences?
 
Alarm issue update.

Seems nothing to do with the lights.

Every time I lock the car I get a beep as if its indicating one of the doors, bonnet or boot are open when they are definitely closed.

So have opened & closed each one then lock the car and when doing the passenger door, the car the alarm does not beep and the alarm does not go off.

But then if I turn the ignition on (I put the car back in the garage), lock the car and I get the indicator beep again.

I open and close the passenger door, set the alarm, no beep.

Confused.

 
Doesn't seem to be the door either.

I was assuming that the alarm was only a perimeter alarm activated by doors, bonnet & boot.

Have just spoken to my indy and he reckons it is also volumetric, the sensor being deactivated when the car is locked with the roof down.

So I have put the roof down, locked the car - no alarm, as yet.

So it appears to be whatever is the cabin sensor.

 
Alarm still going off intermittently.

Would a low battery cause the alarm to go off intermittently?

Just tried to drop the roof by the remote and nowt happened.

Got in the car to do it and inserting the key fob, message on dash is "low battery"

Its still the original Porsche battery, assuming from new, so have just put it on a trickle charge.

Haven't been out in the car out for a month but do start it up very so often to move it out of the garage and back in to get access to stored DIY tools etc etc.

 
Keith,

Just to mention that in addition to the doors and the front and rear boot-lids, you can also get an alarm beep if the dashboard cubby lid is open.

A low battery level can throw up some spurious problems, and if it's the original battery and hasn't regularly been on a battery conditioner then it may be time to fit a replacement.

Jeff

 
Yes Jeff, considering the car is 7 years old and I assume the battery is the original, and bearing in mind the short runs I have been doing this year with the in/out of the garage movements which doesn't do engine or battery any good (although I do try to keep these to a minimum), then all things being equal then it may well be time for a new battery.

I have a C-Tech trickle charger which I use for my other three cars because for their even further lack of use than the Boxster but perhaps during a period of idleness then I should connect and leave it on the Boxster.

Will wait until I get the green light on the C-Tech and then see what happens.

And I hadn't realised that about the glove box, will check that out.

Thanks.

 
Well, I have had the main battery on trickle charge/conditioning for a few days until the green light on my C-Tech charger was on more than it was off, and on locking the car I am still getting the chirp from the siren/sounder (although it is not going into alarm after locking it) so it does appear to be the rechargeable battery in the sounder nearing the end of its life.

Looks like I will need to get the dremel out and take the sounder apart in order to replace the battery as per the boxa.net link.

Thanks for the link Gordon.

 
A long shot as some one has mentioned glove box also try the centre arm rest this is a common one missed

 
I have checked both glove box and centre console but no change.

I am still getting the chirp but its not going into alarm like before so perhaps it is an early warning that the sounder battery is on the way out.

But without the helpful advice of the forums, how is one to know?

 
After further investigation which found a thread on this very forum from 2010 about another owner with the same problem and not on a Boxster.

The siren is in fact the tilt sensor and hence is driven by its own battery to deter a prospective thief getting into your car, disconnect the main battery and then try to tow your car away. Apparently its fitted to comply with Thatcham Cat 1 alarm system requirements.

I have now just disconnected and removed it (one torx screw and a multi-connector)

Mine is a VW Audi part, Cobra Automotive Technologies, made in Italy

The offending part

https://www.design911.co.uk/fu/prod135534/Alarm-Siren-for-Tilt-Sensor-Porsche-981---991---970---918---958/

Found used ones on Ebay for £10-20 but obviously the condition of the battery would be unknown.

Part no. is 1K8 951 605 B

 
Thanks Jeff.

Re 903-000, items 1 & 2 are the main horns, it is item 5 which is the tilt sensor/sounder.

Just dawned on me that the tilt sensor/sounder might be the siren for the main alarm although am sure have read somewhere that the main horns are used for the alarm.

I will set the alarm with the tilt sensor now removed with me in the car and then open the glove box or centre console and see (hear) what happens.

Have just read the parts list, yes 4 says signal horn for alarm system & 5 alarm horn.

The plot thickens

 
The cable for the "tilt sensor/sounder", item 9, is listed as "wire set modification kit signal horn" which sort of confirms earlier threads that this unit was a retro-fit of sorts

 
Just done a couple of tests, locking the car & setting the alarm with me in the car.

With one press of the remote lock, any movement inside the car activates the alarm but with the sounder removed its visual only with the indicators flashing.

With two presses of the remote lock, deactivating the interior surveillance, on opening the glove box for example, again indicators flashing only.

So presumably that means the only audible alarm is the sounder which I have removed.

So from parts catalogue illustration 903-000, its an either/or fitting of the alarm "horns" parts 4 or 5.

And have just noted, on the part number list for part 4 states - signal horn for alarm system use if required.

So perhaps part 4 is a siren only

Part 5 has the tilt sensor for Thatcham Cat 1 compliance.

 
Having received my new battery through the post and now cut open my tilt sensor/sounder unit, I don't think the problem is the battery.

The battery is kicking out 6.3 volts but there is corrosion in one area of the PCB around a few of the components so I think it is curtains for the unit.

Obviously water has got into the unit, somehow

 
Second hand replacement alarm sounder arrived today.

However, I purchased a 1K8 951 605B as that is what I removed.

What landed on my door mat was a 1K8 951 605.

Typical ebay, or should I say typical vehicle breaker.

However, I have connected it to the car and all seems well.

Alarm works when opening the glove box for example, moving in the car when when the alarm is set and not going off when it shouldn't. !!!

 
You must log in or register to reply here.

Posts made and opinions expressed are those of the individual forum members

Use of the Forum is subject to the Terms and Conditions

Disclaimer

The opinions expressed on this site are not necessarily those of the Club, who shall have no liability in respect of them or the accuracy of the content. The Club assumes no responsibility for any effects arising from errors or omissions.

Porsche Club Great Britain gives no warranties, guarantees or assurances and makes no representations or recommendations regarding any goods or services advertised on this site. It is the responsibility of visitors to satisfy themselves that goods and/or services supplied by any advertiser are bona fide and in no instance can the Porsche Club Great Britain be held responsible.

When responding to advertisements please ensure that you satisfy yourself of any applicable call charges on numbers not prefixed by usual "landline" STD Codes. Information can be obtained from the operator or the white pages. Before giving out ANY information regarding cars, or any other items for sale, please satisfy yourself that any potential purchaser is bona fide.

Directors of the Board of Porsche Club GB, Club Office Staff, Register Secretaries and Regional Organisers are often requested by Club members to provide information on matters connected with their cars and other matters referred to in the Club Rules. Such information, advice and assistance provided by such persons is given in good faith and is based on the personal experience and knowledge of the individual concerned.

Neither Porsche Club GB, nor any of the aforementioned, shall be under any liability in respect of any such information, advice or assistance given to members. Members are advised to consult qualified specialists for information, advice and assistance on matters connected with their cars at all times.

Porsche
Lockton
Pirelli
Officially approved
Oracle Finance
WEX Esso
Collecting Cars
Archant Dialogue
Back
Top