Alarm activating everytime the car is locked

Evening All

For no apparent reason, the alarm on my TD5 is going off after 10 seconds from locking it using either the fob or key. The dashboard alarm light seems to rapidly flash as soon as it's locked all the time.

Could this be a "one of many things" problem? I've opened and closed all the windows and doors, including the bonnet, but the alarm still activates after about 10 seconds.

The engine starts ok and the dash alarm light goes off when the ignition is turned on.

Cheers

If the ultrasonic unit same as p38 it coud well be that

if you lock it with one door or bonnet opened do you get misslock warning(short horn sound)?

I'll try locking it with a door open this morning. If I do or don't get the short horn alert, what will that suggest?

Thanks

do the test then we'll speak cos it's complicated, in case you hear the misslock warning, do another test, lock with all the doors/taildoor/bonnet opened then unlock and lock each time after you close them one by one and if it happens one time to not get the misslock with one opened tell me which one...if no misslock you need tester

Check that the volumetric sensors aren't corroded on the PCB through leaking sunroofs.

Peter

Shimsteriom said:

...the alarm on my TD5 is going off after 10 seconds from locking it using either the fob or key...

Click to expand...

which rules out the volumetric alarm doesnt it?

sierrafery said:

which rules out the volumetric alarm doesnt it?

Click to expand...

Possibly, but they have a mind of their own once the PCB gets corrosion damaged, so I wouldn't rule them out, and worth a minute to pop them out and check.

Peter

when the car is locked with the key the volumetric alarm is completely disabled so IMO it doesnt matter how the ultrasonic sensors are... water ingress or corrosion at the BCU would be more suspect in this strange case... though with a LR we'll never know for sure

I get the single horn blast if I try to lock the car with any of the doors or bonnet open. I have tried each individually.
I have also tried the reverse and opened all the doors and bonnet and then closing one at a time, and tried locking it each time. I get the single horn blast each time.

The alarm goes off after 10 seconds even if you lock it with a door open?, if yes leave the driver's door open, lock and when it goes off dont unlock just try to start the engine... is it immobilised then(no crank at all)?, also when you lock with the key the central locking work for all the doors?

If I try to lock it with any door open, the alarm won't activate. It just gives a single horn blast to indicate that one of the doors are open, so I'm not sure how I can check the engine immobilisation if I can't set the alarm with the doors open.

Yes, the central locking works on all the doors when the vehicle is locked using either the key or fob.

Thanks

when you lock with one door or bonnet opened the alarm should be armed in partial armed status and work for all the other not closed doors.bonnet, if it's like you say that with misslock it doesnt go off after 10 seconds(you should have said that from the beginning) dont do that test with immobilisation cos we are getting closer...it's a very strange issue, let me think deeper about it, untill then unplug the bonnet switch and lock this way cos it should give you the misslock and not go off even if it's armed for all the doors then

by the way, if you lock with the dirver's door opened it doesnt go off but what if you shut that door then?...it stays silent?

I appreciate your help

Hi

I've just disconnected the bonnet switch and set the alarm..... It has activated, but the alarm hasn't gone off!

I'll get a new one ordered. Thanks very much for pointing me in the right direction.

It might not be the bonnet switch though just that with it disconneted the alarm is partially armed and that's why it doesnt go off... you can try to bend it's bracket a bit upwards to improve the switch's travel and plug it back... as i said your's is a very strange issue, the bonnet switch has different input than the doors cos it works with voltage on the earth path that's why it can make some tricks especially if it has some water ingress...we'll see, with it disconnected all the alarm must work normally except for opening the bonnet while it's armed

Spoke too soon, everything was fine until locking the car outside my office this morning. Now the alarm is going off again when locked. The bonnet switch is still disconnected.

I don't suppose anyone can suggest any other possible causes?

I was kinda expecting that... you need to plug it in a tester tosee some settings... meanwhile try to lock with the key again just to make sure it's not the volumetric alarm(make sure you dont axccidentaly push the fob button while you are doing that), and do that test with the door open lock then shut the door

OK. So if I lock the car using the fob, the alarm goes off shortly afterwards, however, if I use the key to lock it, the alarm doesn't go off.

Does this mean it's the internal movement sensors that are at fault?