Topic

Hi .. I know this has been talked about MANY times before, but I can't see what is going on here Any help appreciated

Symptom - Alarm goes off randomly

What I have tested
1) Battery - Condition good, fully charged (used a battery checker)
2) Alternator Good (battery checker)
3) Used 'Alarm Test Mode' tested all the sensors except the volumetric, all are good

BUT

when we lock the car now ... key fob or by key, the central locking makes a racket as it tries to open and close the door locks. This happens for a while, and then it goes away.

This may be what is causing the Alarm to go off.

So anyone else ever had their central locking basically switching on/off of its own accord (with no key)? and if so what needs fixing

Most appreciated

Thanks Community

Regards
Tim

Apologies if in wrong category ..... Newbie

Are you sure that the alarm going off randomly and the 'machine gun' effect from the locks are both symptoms of the same fault as they sound seperate things.
.Guidence on both exists btw

We think they are related, as the Alarm sensors seem ok
The lock thing has only just started happening ... since the car was serviced !
Thanks for the reply
I'll go searching

One of the main causes of the alarm going off randomly seems to be the state of the wiring to the boot lid, the wires by the hinge can both fail and short causing some very odd problems including the alarm going off without apparent rhyme or reason. The wires around the boot hinge have been replaced on very many TFs, sometimes more than once

Notanumber wrote:

One of the main causes of the alarm going off randomly seems to be the state of the wiring to the boot lid, the wires by the hinge can both fail and short causing some very odd problems including the alarm going off without apparent rhyme or reason. The wires around the boot hinge have been replaced on very many TFs, sometimes more than once

Sadly, Notanumber's observations are very true, and his suggestion is exactly what I first thought when I read your post. If the engine cover was removed when your car was serviced, the loom near the boot lid hinge MAY have been moved when the air filter was replaced, or other work in that area done.

Good luck finding the actual cause and when you do find & sure it, please let us all know, for the sake of future sufferers! I have been lucky so far, but my 2002 TF spent most of it's life in the (only) previous owner's garage, with just a few hundred miles at most between each of the MOT's!

We had that loom sorted once before ... but that was due to the brake lights being on all the time Might have to get it checked out. Thanks

I used to have problems with the alarm going off for no reason plus the car battery only lasting a few days without a run. I traced my problem to the backup sounder. The case had let water in and the little internal back up battery was exploding inside. I had no option than to get a new sounder.

I have an update on this problem ...for anyone interested

I charged the battery to 100%, reconnected it and we still had the same problems (Central locking and Alarm), so I decided we needed a new battery (it is over 4 years old).
I bought a new battery, a good quality Bosch S5. When I came to fit the new battery I rechecked the old one. The old one had dropped from 100% to 57% and it had not gone anywhere. So I thought at least the new Battery was needed.
I fitted the new battery, reconnected and still had the Central locking and alarm issues
So we gave up and checked it in to a specialist.
Three days later, my wife tried the central locking again and the darned thing worked properly !
Today (Sunday) I put the new battery on charge ... and it took 4 hours to reach full charge !
I reconnected, and again all systems seem ok.

So, puzzled. It might appear that there is some other system on the car that needed charging up perhaps???
So the old battery was not good enough to keep things charge, but after 3 days the new one was ?

Sounds mad ,,,,,,

We still have the car booked into the specialist for a week tuesday should this madness return.

But for now the problem has gone away.

It may be the alternator is providing less charge than it should but enough to still allow the battery to slowly charge with the engine running. The sure fire way to prove this is to measure the voltage across the battery when the engine is running, it should be 13.5 volts or more. If the number starts with a 12 instead it points to a lossy alternator.

I will check that too.

The battery checker I bought from Amazon also has an alternator check .. and that seemed ok.

With the engine off it was ~12V, when cranked it dropped to about 9V, and then jumped to 14V .. so hopefully OK

The 14 volts reading is encouraging. How long had you run the engine for before turning it off and checking the voltage ? I would usually expect a battery at rest to read 12.5 or a little higher if the car has recently been driven normally. 12 volts seems a bit too low, as though the battery hasn't had enough time to charge.

It was basically a 1 min test, where you start analysing then start the car, and idle for the rest of the duration.

I will do the test again though.

The car is going out tonight, so we'll see how that goes

Thanks