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View Full Version : My Alarm is too "sensitive".


Simplex
Feb 26th, 2006, 16:41
Is there anyway way of "turning down" the sensitivity of the alarm system on my 1998 850 dti auto estate.

I've always locked the car with the remote fob. The car as always been sensitive to strong winds or hailstones, even thunder sets it off.

I've taken now to locking it with the key, but I'am not sure if this gives me any alarm settings.

Any advice would be welcome.

Thanks.

STE-MAL
Feb 26th, 2006, 17:43
Is this a standard alarm system? I didn't realise they were adjustable.

robtd
Feb 26th, 2006, 19:48
hi mate

when i first got my 850 t5 i thought the alarm didn't work at all. then i noticed that the alarm horn under the bonnet was unplugged. maybe it was too sensitive for the previous owner.

maybe you could do this - immobiliser and dead locks will still work then

STE-MAL
Feb 26th, 2006, 20:17
Hi robtd my friend, the best way to find out if all is well is to plug it in and try it! Best of luck.

robtd
Feb 26th, 2006, 20:21
it works fine mate

plugged in and singing away when required - just wondered if it may have been too sensitive for the previous owner

unplugging it may be a solution for this chap

cag
Feb 26th, 2006, 20:26
if it is a1998 v70 the ultrasonic sensors in the B pillars were being replaced as they were too sensitive best way to tell is to take it to a volvo or independant repairer and get the alarm causes read.

Mike Stead
Feb 26th, 2006, 20:32
if it is a1998 v70 the ultrasonic sensors in the B pillars were being replaced as they were too sensitive best way to tell is to take it to a volvo or independant repairer and get the alarm causes read.

Hey, I got one of these (V70 1998 AWD with the ultrasonic sensors). Was there a recall for them? Ours has gone off enough in the wee small a.m. that we now don't lock it at night using the alarm. People have reckoned it was probably bugs etc.

Cheers,

Mike

cabman
Feb 26th, 2006, 20:36
I have the same problem with my new C70 convertible. Volvo told me to remove any metal objects from the centre consol and armrest - made no difference. What is the answer to the problem raised by Simplex?
I now lock the car by following the instructions as though leaving dogs etc in the car, ie
Hold down the lock button inside the drivers door. The door locks then unlocks. Get out and lock with the remote. All is now set apart from the interior volumetric sensors. Works for me but need to know how to cure it.
Is it a microwave sensor? Had one on a renault which I could tune with a small screwdiver.
All ideas welcome.
Tony

Steve B
Feb 26th, 2006, 23:02
I have the same problem with my new C70 convertible. Volvo told me to remove any metal objects from the centre consol and armrest - made no difference. What is the answer to the problem raised by Simplex?
I now lock the car by following the instructions as though leaving dogs etc in the car, ie
Hold down the lock button inside the drivers door. The door locks then unlocks. Get out and lock with the remote. All is now set apart from the interior volumetric sensors. Works for me but need to know how to cure it.
Is it a microwave sensor? Had one on a renault which I could tune with a small screwdiver.
All ideas welcome.
Tony

Yes, was told the same by Volvo - do not leave any coins in the coin tray in centre console as it interferes with alarm (great design if true!!). Anyway, having not put any coins in for 18 months, the problem is sorted.

Mike Stead
Feb 27th, 2006, 06:09
Yes, was told the same by Volvo - do not leave any coins in the coin tray in centre console as it interferes with alarm (great design if true!!). Anyway, having not put any coins in for 18 months, the problem is sorted.

IMHO, that's crazy talk! the car is full of metal - the seat frames, heated seat/electric seat wiring/elemants/motors, the handbrake, gearbox, etc.

And the alarm is ultrasonic. It's not a metal detector. Like a bat's satnav, it is looking for a change in the ultrasonic reflections it receives to detect movement in the cabin. If any coins in the tray don't move, how could they set it off?

Of course, if that has solved your problem, maybe it's me who is crazy ;-)

Love to hear the opinion of an alarm expert here.

Sprintman
Feb 27th, 2006, 10:20
Hi all, I've a similar problem with my '96 855, the alarm goes off all by itself, usually at some most inconvenient hour in the middle of the night. I assumed that it might be somehow temperature related as it seems to happen more frequently in the summer when the temperature drops overnight, but there is a 'buzz box' moped that sometimes passes by and sets it off. I was told by my dealer [Pillings, Welwyn] that it is the glass break sensor on the screen pillar that has been setting the alarm off [last 10 events stored in memory]. The sensor, as far as I know, is not adjustable, it is 'hard wired' into the alarm, and a replacement sensor is 70. I was also told not to keep coins in the coin tray [I don't], but as has already been pointed out the car is full of metal, so what difference would some coins in the tray cause?

Simplex
Feb 27th, 2006, 14:28
Hi all,

Thanks for the replys.

Just asked my local Volvo dealer about the sensitive alarm.
They need to put in onto the machine, and will have to charge me 47 for half an hours labour. "Bl--dy silly money".

Does anyone know of an Volvo Indepentant garage in the Durham/North East area?.

Cheers, Simplex.

cabman
Feb 27th, 2006, 20:01
I have taken the coins out of my C70 slots and, guess what? No faulty alarm (yet!)
Taking it in under warranty if it goes off again though.
I'll keep you all posted!
Tony:speechless-smiley-0

s40euro
Feb 28th, 2006, 08:22
I do not know the exact name for it but it must be hood latch or whatever triggers the alarm due to faulty switch.

First try to find an other one from the junkyard and try it.

Also your siren might be defective and it begins to play in the middle of the night.

But form what you said it seems hood latch/lock assembly is faulted.

ollieoxford
Feb 28th, 2006, 11:27
I'm no alarm expert, but my first impression is that a pile of small coin's would resonate when hit by ultrasound, and this amplified signal returning could trigger the alarm.

Now this may be a stupid suggestion to a cure, but it may be worth trying (unless anyone can already talk with experience) -> cover the ultrasonic sensor with some masking tape and see if it makes any difference. At worst it'll set the alarm off straight away, at best it'll attenuate the signal and make it less sensitive?

Simplex
Mar 3rd, 2006, 21:22
Thanks for all the posts,

Just a quick undate.

I had my car in today (Fri 3th March) for a service and managed to strongarm the garage into checking out the alarm fault codes for free.

It is the glass breakage sensor that is at fault. They have cleared the faults for me and say that it may now work ok, but no promises. A replacement is 130 total. I will not be paying that sort of money.

Just in case in acts up again, does anyone know what is involved in fitting a second hand one.

Cheers.

s40euro
Mar 4th, 2006, 21:43
Thanks for all the posts,

Just a quick undate.

I had my car in today (Fri 3th March) for a service and managed to strongarm the garage into checking out the alarm fault codes for free.

It is the glass breakage sensor that is at fault. They have cleared the faults for me and say that it may now work ok, but no promises. A replacement is 130 total. I will not be paying that sort of money.

Just in case in acts up again, does anyone know what is involved in fitting a second hand one.

Cheers.

As long as I remember

Remove the grilles above the fron speakers ( I think also the speakers)

Tadaaa there it is (If it is the fron sensor)

If it is the rear sensors they must be on the rear windows just try to repair with some conductive paint the paint used to repair for the rear window defroster.

On monday I will be able to check the well known sw about repair and part numbers.Then I will give more clear answer.