D3 alarm going off for no (good) reason

[V2Evo96]

2009 D3 4.0L 88,000k's theft/break in alarm has gone off 3 times in about 3 weeks for no apparent reason.

In each instance door/tailgate/bonnet/etc checked - all closed properly.
In 2 of 3 instances vehicle parked in slightly windy conditions.
In all 3 instances ambient temps were warm with sun shining but not 'hot'. In all 3 instances alarm went off again within about 5 minutes of reset.

Alarm never goes off under carport at home in middle of the night :-) (so far)!

I haven't done a battery terminal 'reset' as yet but thought I would ask if others have experienced this and if so what worked to stop it.

Thanks for any inputs in advance.

[~Rich~]

My first thought would be the bonnet catch switch. Have you had any "bonnet open" messages pop up in the past?

[BigJon]

Moth inside the car? That has been enough to trigger the alarm in my Vogue.

[Epic pooh]

Haha my alarm did not sound even after someone bent a door frame, beat up the door and after much bashing managed to smash a window to pinch stuff off the front seat (did about 5k damage). Good alarm that is :)

[rufusking]

Do you "Double lock" the vehicle, I.e. Press the lock button on the remote twice within 3 seconds, which sets the interior (volumetric) protection or just single lock so that the doors, bonnet tailgate are triggers?

I'd monitor the locking method to see if something is triggering the interior sensors or the external entry points.

I've had the left rear door switch replaced twice by the dealer (under warranty) as that is what has been showing up as the trigger for false alarms. I'm a bit sceptical as the probability of two failing seems remote. I'm guessing a connector or broken/ pinched wire along the line of that circuit is the culprit.

A system scan should show up what is triggering yours.

[rocmic]

My first thought would be the bonnet catch switch. Have you had any "bonnet open" messages pop up in the past?

x2
Cheers
Mike

[Rich84]

Or windows down? Mine sometimes goes off when I leave the windows slightly down or the sunroof tilted. Ultrasonic sensors get set off. My Audi S4 was particularly bad for this as the sensors were mounted right at the top of the B pillars where they were directly in the way of any breeze etc. RRS is not so bad.

[Tote]

x2
Cheers
Mike

X3, on mine the giveaway was that it got too embarrassing to go shopping as I'd always just make it inside when the alarm went off.
I'd very occasionally get the bonnet open message also, the switch only needs to go open for a millisecond to set the alarm off but not long enough to register on the display.

Regards,
Tote

[V2Evo96]

Thanks all, good input!


RICH
On one of the failures I got the bonnet open message but nothing on screen for the other two.

RUFUSKING
I should have mentioned my model is the SE - I don't believe there is an interior alarm as there is a plactic fascia where the sensor would (should) be. I believe the double lock feature on the SE ensures that no one inside can open any doors/windows (which I think is pretty silly if someone inside NEEDED to get out of the vehicle. I could be wrong....

RICH 84
no windows down or cracked open.

TOTE
Thumbs up for that info.
------------------------------------------------------------------

I'llplug in the scanner and see if I can find the 'security' information. After that I will do the battery disconnect and terminal touch to reset.

Cheers all and be safe out there!

[Tote]

My quick fix was to cut and join the wires for the switch located in the bonnet latch until I could get a new switch. At least I could lock the vehicle and walk away.......

Regards,
Tote

[LeighW]

Thanks all, good input!


... I believe the double lock feature on the SE ensures that no one inside can open any doors/windows (which I think is pretty silly if someone inside NEEDED to get out of the vehicle. I could be wrong....

...

Cheers all and be safe out there!

Don't worry V2Evo96, in the event of an accident all doors are automatically unlocked. Might be related to airbag deployment but I believe that emergency service people can open all doors after any accident that deploys airbags. It is a safety feature that was quoted for the D3 on release in 2005 IIRC.

And as stated before, first check the bonnet catches' micro-switches, left and right sides, as they may even trigger the alarm if the car is locked when the bonnet is slightly twisted due to wheel placement. Happened to me when I knew all doors were closed propperly.

HTH

[wombathole]

My quick fix was to cut and join the wires for the switch located in the bonnet latch until I could get a new switch. At least I could lock the vehicle and walk away.......

Regards,
Tote

X4. I bent a paper clip into both holes of the bonnet switch connector and have had no problems since.
Andy.

[V2Evo96]

OK - definitely the bonnet switch - I have looked high and low for the actual switch so I can kill it off but can't find the @#@$% thing....
I've looked in the latches, around all the edges and same on the bonnet itself and no go.

Sorry to ask, but could someone tell me where it is so I can put a stop to it and keep the vehicle locked?

Thanks in advance for help with this!

Cheers, V2

[Tote]

Its in one of the bonnet latches, can't remember which one but if you look closely you will see a flat actuator that gets pressed down when the bonnet closes.
Part number is LR041431

Regards,
Tote

[V2Evo96]

Thanks Tote,

I was looking for it at night with a torch so must have overlooked it. Will check again today and pin it with a paperclip as others have done.

Cheers!

[~Rich~]

Pop your grill off, 4 tabs at the top and two on the sides underneath the bar.
This is the micro switch underneath the lock on the drivers side on a D3.
https://www.aulro.com/afvb/images/imported/2014/10/1401.jpg (http://s193.photobucket.com/user/VSK5/media/D3/F132C2E3-9C03-4176-B44F-DCC7DEAE05A3_zpsprshtd6o.jpg.html)

You can see the offending part of the switch where my finger is pointing to the shiny part of the switch.

https://www.aulro.com/afvb/images/imported/2014/10/1402.jpg (http://s193.photobucket.com/user/VSK5/media/D3/D2AC3738-70BE-48DA-B0B1-3C1DF9951682_zpsgumavtxo.jpg.html)

You can either replace the switch or do what I did and muck around bending it until it works correctly.
Or do the paper clip/ wire trick.

[V2Evo96]

FOLLOW UP

Rich, thanks for your time taken to photo the latch and switch - love this site! So helpful indeed.

My problem turned out to be the cable connector just inside the bonnet behind the latch - easy to reach without removing anything.

The connector was loose as I could tell it wasn't clipped into the latch. I pulled the connector off, sprayed some electra clean into the socket and the pins, then pushed it off and on a number of times to "shine up" the connection.
Finally latched it into position and voila' ---no more intermittent alarm (so far so good).

Thanks again all for your kind assistance.

[Roulston]

IO just wanted to add to this thread as alarms problems are so annoying.

I had the same problem on my Freelander and tried everything. Alarm resets, vacuuming air vents to catch any huntsman spiders. Etc.

At the next service the mechanics confirmed the bonnet switch and it us a common fault. They did a bypass while they ordered a new switch which they will replace at the next service.

It seems that the bonnet latch or wires are a most common alarm fault.

Tony

[V2Evo96]

Over a week now and no spurious bonnet alarm since I cleaned and re-latched the connector..... (as yet anyway)...