996 Nuisance Alarm
Discussion
Not looking for any advice here as I believe the issues in following paragraphs to be addressed - this is just a record for other 996 owners who may run into similar issues.
For the last couple of years my 996 C2 3.4 has had the odd speight of false alarms which has proven to be difficult to diagnose correctly.
This may not be 100% accurate but from what I’ve learnt I believe the alarm siren can be triggered by the following:
1) Interior motion sensor
2) A number of microswitches - door handle mechanism, bonnet latch, glove bin and radio...etc... there are more.
3) A tilt switch - if the car believes it is being towed - this tilt switch is located externally under the scuttle panel on early 996's then moved to under the passenger seat in later models.
4) Detection of a voltage drop - triggered by battery disconnection without the key in the ignition [see owners manual] or if the voltage of the battery gets to low or faulty even fuses.
5) Siren fault
As I have experienced, 1 to 4 create a code in the cars system log which can be read (using a specialist tool e.g. Durametric) to give an indication as to the reason why the alarm may have sounded, however this may not be the complete picture.
Working through the issues:
Initially - I have had the tilt sensor replaced (and moved to later version) under direction from an OPC as it had failed causing the alarm to trigger constantly. The siren could be disabled with a press of the button on the key fob. For information this sensor can be coded off in software.
Secondly (and months later) replaced microswitch in drivers door handle and centre glove bin as there were codes linked to the siren activation. Again the siren could be disabled with a press of the button on the key fob.
Thirdly (a month ago just as it started to get cold out) even though my car is connected to a CTEK in a garage i have had a battery go dead within 3 years resulting in voltage drop and alarm siren activation - in this case i was not able to stop the siren from going off even through button press and starting the car - had to wait 5 mins for the alarm to stop - but this is likely linked to the last issue. Battery replaced under warranty.
Most recently (last couple of weeks and the reason for this post), despite having no codes the alarm siren would activate - luckily this was observed by an independent dealer while in their care and confirmed the issue by replacing the siren - When the siren activates during this scenario it cannot be turned off by a key press. Again have wait 5 mins to stop, at which point it may activate again...much to the delight of Mrs B. Since the siren has been replaced (with a used item) over three weeks ago, I've not observed any false alarms which plagued the car on an off for the last couple of months, to the point it couldn't really be used as it would go off even when filling up with fuel or just driving down the road an hour into a journey!
Hope that helps any future people.
Cheers,
Bloitus
For the last couple of years my 996 C2 3.4 has had the odd speight of false alarms which has proven to be difficult to diagnose correctly.
This may not be 100% accurate but from what I’ve learnt I believe the alarm siren can be triggered by the following:
1) Interior motion sensor
2) A number of microswitches - door handle mechanism, bonnet latch, glove bin and radio...etc... there are more.
3) A tilt switch - if the car believes it is being towed - this tilt switch is located externally under the scuttle panel on early 996's then moved to under the passenger seat in later models.
4) Detection of a voltage drop - triggered by battery disconnection without the key in the ignition [see owners manual] or if the voltage of the battery gets to low or faulty even fuses.
5) Siren fault
As I have experienced, 1 to 4 create a code in the cars system log which can be read (using a specialist tool e.g. Durametric) to give an indication as to the reason why the alarm may have sounded, however this may not be the complete picture.
Working through the issues:
Initially - I have had the tilt sensor replaced (and moved to later version) under direction from an OPC as it had failed causing the alarm to trigger constantly. The siren could be disabled with a press of the button on the key fob. For information this sensor can be coded off in software.
Secondly (and months later) replaced microswitch in drivers door handle and centre glove bin as there were codes linked to the siren activation. Again the siren could be disabled with a press of the button on the key fob.
Thirdly (a month ago just as it started to get cold out) even though my car is connected to a CTEK in a garage i have had a battery go dead within 3 years resulting in voltage drop and alarm siren activation - in this case i was not able to stop the siren from going off even through button press and starting the car - had to wait 5 mins for the alarm to stop - but this is likely linked to the last issue. Battery replaced under warranty.
Most recently (last couple of weeks and the reason for this post), despite having no codes the alarm siren would activate - luckily this was observed by an independent dealer while in their care and confirmed the issue by replacing the siren - When the siren activates during this scenario it cannot be turned off by a key press. Again have wait 5 mins to stop, at which point it may activate again...much to the delight of Mrs B. Since the siren has been replaced (with a used item) over three weeks ago, I've not observed any false alarms which plagued the car on an off for the last couple of months, to the point it couldn't really be used as it would go off even when filling up with fuel or just driving down the road an hour into a journey!
Hope that helps any future people.
Cheers,
Bloitus
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