Xantia Alarm is driving me mad!!!!

[Mandrake]

I didn't realise that the volumetric sensors could be faulty perhaps but I don't think they are causing the beep on setting the alarm,

That's correct - faulty volumetric sensors won't cause a beep when you arm the alarm because they don't become active until the alarm has been set for 45 seconds - this is to give time for the air in the cabin to stabilise as even a breeze in the car will set it off.

looks like I shall be spending a lot of time on this one wasting a nice sunny warm day sometime soon.
The link provided does give a method to test for another reason for the beep on setting the alarm without the use of a lexia so I shall now check the bonnet by leaving it open before setting the alarm to see if the beep stops.
cheers.
Nigel.

I can almost guarantee it will be either your bonnet switch or your boot switch.

You can rule out the passenger door switches easily:

1) If pressing the lock button on both front doors operates the central locking as it should then the lock switches are fine.
2) If opening each passenger door lights the interior lights and turns on the door ajar warning light on the dashboard, AND the door ajar warning light goes out when all 4 doors are closed, the door open/close switches are ok.

The same switch contacts are used for both central locking, interior light control and alarm triggering, (I just double checked the wiring diagram) so if they work the interior lights properly they will be working correctly for the alarm too.

If the above tests passed ok it MUST be the boot or bonnet switch. On a hatchback the boot alarm switch is down beside the loop clasp under the black plastic trim in the bottom of the boot. Not entirely sure where it is on an estate but it is NOT the same switch that operates the boot light, so just because your boot light might be working ok has nothing to do with whether the alarm switch is working. The boot light is a tilt switch in the tailgate. If you can find the alarm switch for the boot (almost certainly in the same basic area as the hatch) then simply unplug it as the switch is open circuit when the boot is closed so unplugging it will make the alarm think the boot is always closed.

The bonnet switch is somewhere in the front grill underneath where the catch pokes into the hole - my bonnet switch does not work (alarm does not go off or complain when the bonnet is left open) but thus far with casual searching I have not found it! Either it has been removed by someone or some degree of disassembly around the catch area is necessary to see it. Again, unplugging the switch will make it think the bonnet is always closed.

[Mandrake]

my S2 Xantia handbook says that pressing the volumetric switch does indeed disarm the sensors but it also makes the alarm flash the headlights only instead of activating the alarm sounder

I'm going to have to double check that because I don't remember reading that in my owners manual.

so people who think they have cured the false triggering could well be suffering the lights flashing over night and not actually be aware of it happening after they have pulled their curtains. in daylight it could be even harder to see the headlamps flashing.

Except I unplugged the ultrasonic sensor for over a week and armed the alarm normally with the fob and without pressing the dashboard button - no false alarms at all. The alarm randomly going off when nobody is near the car is almost always the ultrasonic sensors.

Whilst we are on the subject could anyone actually identify the make of alarm fitted to the xantias please because I'd love to tell my Insurance company what make it is, the alarm details always say Unknown it could be a big Insurance price changer if it is one of the good ones. ACTUALLY scratch that please I found this link all about Citroen alarms can somebody put it up as a useful link please? I am sure there must be a fair amount of people that don't know what make alarm they have.
http://thatchamfitters.co.uk/car/cars-w ... itroen.htm" onclick="window.open(this.href);return false;

The alarm doesn't have a name - its an integrated factory fitted design. The CPH (ECU) in a S2 Xantia is a single unit mounted up behind the glove box that performs transponder chip based engine immobilisation, central locking, interior light control and alarm all in one. It's completely inseparable from the rest of the car - the car won't start or operate without one, and it is permanently keyed to the engine ECU.

[falling-out-with-my-car]

simon,

It is on page 179 of the S2 handbook the handbook implies that the alarm siren can be switched off.
paragraph 1 is a guide for turning off the volumetric sensors paragraph 2 uses the same switch to disarm the siren so even if the driver is not aware of it they may have disabled the siren and only have flashing lights. I do appreciate you have disabled your sensors and genuinely found your fault.
Thanks for the info on the alarm make so that Thartcham link is nonsense, then?
Regards
Nigel.

[citroenxm]

Mark one sirens have a key switch in the scuttle passenger side to switch it off..

series two alarm systems dont but work in a slightly different way. For example when you first connect a series two battery theres no need to rush to reset the system by pressing the siren button on the dash and switching on. Theres no need. Only in series one cars..

the alarm system is a "texton" unit. Ive no idea if its thatchem approved though. Probably not. Who knicks a xantia?

They do have electronic dead locks though on series one and two. Press the lock button on the fob and press it again for dead lockm OR lock the key in the door and hold the key in the turned position for a few more seconds and it will dead lock.

another siren activation is if you lock the car remotely with the fob but unlock it with the key in the door this will set the alarm off (in series two cars only)

[Timmo]

mine was the boot switch, i kinda cheated it by pushing in the microswitch on the boot catch and locked the car (remote before the wife broke it), resulted in the car locking with no beep, the boot catch wears over the years and no longer has the height to push the boot microswitch up enough, Or, pushes it up but once fully spun to lock position there isnt enough plastic left to keep the microswitch in the Closed position,
i never bother locking the car down here, but ave on a recent trip to mothers in Wells due to some oik trying to get into the boot the last time we were there! - was a pushchair, jump leads and umbrella in it then! but it didnt beep then, Probably more in shock its Actually been locked!

[falling-out-with-my-car]

Timmo,

is this your 1998 S Reg estate your talking about? (same as mine)
if so are you saying that the micro switch is down near the actual locking mechanism at the bottom of the rear door
or is it up behind the handle? above the number plate.
Nigel.

[Timmo]

It's on the lock unit fella, clips onto the lock catch casing so when the lock catch Spins it pushes in the switch,

[falling-out-with-my-car]

Timmo,
can you be a little more specific please?
the lock unit you speak of I gather you are referring to the mechanism behind the handle which is above the number plate on the estate yes? its a jungle behind my boot door panel. please bear in mind I only have one good eye and had cataract surgery on the other yesterday so locating things is a bit hit and miss at the moment until I get some new close vision glasses
thanks again.
Nigel.

[Timmo]

Sorry fella, bottom of the boot, the part that catches to the bar on the boot floor, as the mechanism spins when it connects to the bar on the boot floor, the top of the mechanism that spins has a cam profile that pushes the microswitch in but wears over the years, also they are only a U shape sprung clip which will wear over time too, will try and get a picture for you

[falling-out-with-my-car]

Thanks Timmo,

I know where to look now,
I'll let you know what I find.

Cheers
Nigel.

[Timmo]

No worries,
If yours is like mine was then you can see the microswitch is pushed in as it spins round but comes out just enough when in its final position to not think its shut, iirc you only need to take the boot cover off not the membrane,
I did seach for xantia estate boot lock on teh mighty Google but only saw Thousands of hatch boot locks! Haha! Service.citroen shows them But not together so you can't see the position of them! But the part numbers are 6339 34 for the sensor and 8726 A8 for the tailgate lock, just incase you need them/want them/ bored and fancy a nose!

[falling-out-with-my-car]

the membrane isn't in mine any more I put a very thin line of black body panel glue along the top of the bottom rear windscreen seal in very hot weather it dried quickly, so thin you cannot see it unless you look very hard it has stopped all the water passing through the boot door, it would only become a problem if the rear windscreen broke and a new one was put in. actually if you were confident a tube of windscreen seal glue might do the same job.
Thanks Timmo I'm an R/c modeller building model boats in my spare time so I'm sure I can come up with a fix once I have located the problem there isn't nothing a dob of aeroldite or superglue can't fix. actually for worn plastic cams aeroldite is a great builder which can then be sanded to shape. I've seen this done on plastic valve cams controlling flow of steam to mini turbines on two calor gas converted steam engines in a model boat.
Thanks again will take a look soon when the eye feels better.
regards.
Nigel.

[Dodger]

I've just jumped onto this thread because I've had a problem with the tailgate lock on my 2000 Xantia 2.0 HDI, which seems to tie in with some of the above.

Basically the locking and unlocking of my tailgate was very hit and miss, so I've had the interior panel off and checked and lubricated everything. The tangs either side of the locking pawl were a bit bent in towards the pawl so I've straightened them up, and everything is now working fine except............ every time I use the button on the remote control key to lock the car, the horn gives a little toot, which it didn't do before.

Reading through the above, it appears that I've disturbed or upset the switch or sensor that tells the ECU that the tailgate isn't closed (even though it is), so it's giving me a toot to warn me.

Can someone tell me exactly where the sensor or switch I've upset is located so I can check it out.

Many thanks.

[Hell Razor5543]

Assuming your Xantia is a hatchback, the switch is operated by the sliding cover that protects the hasp loop (not the lock in the hatch itself). You will need to remove the black cover that goes from one side of the boot to another. Once you have done so you can get at the switch. On Gracie the switch stem was broken, so it was not responding to the boot being closed. As the switch is a 'push to break' type I disconnected the switch (while arranging for a replacement), to fool the alarm into 'thinking' the boot was closed.

[Dodger]

Thanks for your reply. My Xantia is actually an estate so I had another read through this thread and found that someone had already said that the switch I was looking for is operated by the locking pawl as it rotates into the locked position when you close the tailgate.

I've now found it and disconnected it so the ECU now thinks the boot is shut all the time and the tooting has stopped!!