Volvo V50 alarm problem

eDicky

It's a 55 reg Volvo V50 estate, a bit tatty externally but reliable and worth keeping. However, the problem of the alarm sounding for no reason has become worse lately to the point that it's often necessary to leave it unlocked.

I'm not sure but it could be worse in the hot weather. There's no insect flying around inside or any other apparent cause that I can see. It's been doing it occasionally for years but not to such an extent as now.

I asked my regular mechanic to try and disable it last year, but he said it's not possible (?). I'd be most grateful for any suggestions..!

AdrianC

If you lock the car with the key, rather than the remote, does that still arm the alarm?

Also, is there an override for the ultrasonics, so you can test if they're the problem?

Browntoa

Is the car battery in good health ? 

Poor battery health is responsible for all kinds of weird electronic faults on modern cars . 

greyteam1959

I had a car years ago that the alarm would go off randomly on a night.
Damned annoying for all.
Sat in the car in the dark in a lay by waiting for a flight to land & a bl**dy great moth started flying around.
Frightened the life out of me but that was the cause of the alarm going off.
Have a good blast around the inside of the car with some fly spray ??

Norman_Castle

Try asking on here https://www.volvoforums.org.uk/ Very helpful forum.

eDicky

Thanks for the suggestions..!

My key only fits in the ignition, not the door, so I can only lock the car by remote.

I've no understanding of what the car's ultrasonics are and how to override them, I'm afraid.

The battery seems to be fine, it has been a bit low on charge after periods of non-use occasionally, but after a long run and presumed full charge the problem still occurs.

I'm pretty sure I would have noticed such an insect, and this fault began a few years ago.

I'll try to post on the Volvo forum, but it looks a little hard to use on a phone which is all I have these days.

I'm curious whether it's true that there could be no way for the alarm system to be totally switched off or disabled (with the car already securely unlocked by key of course)...

Thanks again..!

AdrianC

eDicky said:

My key only fits in the ignition, not the door, so I can only lock the car by remote.

So you don't actually have a key that fits the door lock? Or there's no obvious keyhole, and you haven't figured out where the hidden manual one is... Clue: Probably the front passenger door, behind a removable cover at the back of the door handle.

shaun_from_Africa

eDicky said:

Thanks for the suggestions..!

My key only fits in the ignition, not the door, so I can only lock the car by remote.

I've no understanding of what the car's ultrasonics are and how to override them, I'm afraid.

When you've turned off the engine and removed the key, press the "enter" button on the keypad below the radio.
This will then set the alarm to "reduced guard" which means that the internal ultrasonic sensors will be temporarily  disabled ( until the next time you shut off the engine and the alarm is turned on).
There is a way to permanently disable the sensors but it's only worth doing this once you have proven that they are causing the problem.

Is your key a large black plastic one with a dull metal clip at the end?
If so, there is a spring loaded release tab beside this. Flick it and pull the metal bit and a skinny key will come out.
This can be used to lock & unlock the driver's door without using the remote. It can also be used to lock the glove box.

eDicky

Well, yesterday morning I temporarily disabled the ultrasonics in the way described by Shaun, and so far the car has remained silent.. 

I also found the skinny key insert for the door, I actually discovered it a few years but had forgotten..!

shaun_from_Africa

I've just checked and what I stated wasn't 100% correct.
When the alarm is set to "reduced guard", it's not only the ultrasonic sensors that are disabled. The tilt sensor (which is what activates if someone tries to lift or tow the vehicle) is also deactivated. Basically, "reduced guard" is for when there is someone or an animal inside the vehicle when the alarm is set and you don't want them moving and setting it off so if your alarm doesn't inadvertently go off with reduced guard, it could be either an ultrasonic sensor, the tilt switch or the associated wiring causing the problem.