Login | Register
SearchMy Stuff
My ProfileMy PreferencesMy Mates RSS Feed
Reply to Topic
Author Discussion

piefacemate

Original Poster:

592 posts

56 months

[news] 
Thursday 16th September 2010 quote quote all
Hi all,

My 2001 XJ8 Sovereign seems to have developed a bit of an annoying problem with it's alarm. After being parked up and locked for a period of time, usually 30 minutes or so, it's alarm will go off for a minute and then stop. The car afterwards is then fine.

I couldn't see any obvious reason why it'd do this, all the windows were fully up and all doors closed. Does anyone have any ideas what could cause it to do this?

Cheers,

Chris

TurricanII

1,119 posts

83 months

[news] 
Friday 17th September 2010 quote quote all
battery voltage dropping? Do you get a couple of brief waring messages about traction control/abs when starting up too?

Jaguar steve

3,369 posts

95 months

[news] 
Friday 17th September 2010 quote quote all
It might be you have a faulty detector or could be nothing more than currents of air moving around inside the cabin or swift temperature changes triggering the ultrasonic movement detectors.

The sensivity of the detectors is adjustable using the Jaguar WDS. Dispite the sensivity being set to low mine still does trigger the alarm occasionally if locked remotely - particurlarly if the car is in hot sun then goes into shade.

If you physicaly lock the car using the key rather than the remote fob then the alarm is set without the movement detectors being armed. Try this for a while and see if that makes any difference

piefacemate

Original Poster:

592 posts

56 months

[news] 
Friday 17th September 2010 quote quote all
TurricanII said:
battery voltage dropping? Do you get a couple of brief waring messages about traction control/abs when starting up too?
I've not noticed anything of the such, but then I've not been looking specifically for it! It flashes all the lights as it does it's start-up diagnostics and the airbag light stays on the longest... but other than that...

I'll make a point of checking next time starting it up.

Jaguar steve said:
It might be you have a faulty detector or could be nothing more than currents of air moving around inside the cabin or swift temperature changes triggering the ultrasonic movement detectors.

The sensivity of the detectors is adjustable using the Jaguar WDS. Dispite the sensivity being set to low mine still does trigger the alarm occasionally if locked remotely - particurlarly if the car is in hot sun then goes into shade.

If you physicaly lock the car using the key rather than the remote fob then the alarm is set without the movement detectors being armed. Try this for a while and see if that makes any difference
Thanks Steve, that does make some sense as I moved the car from a cool underground carpark above ground in direct sunlight when it first did it.

I don't know what the Jaguar WDS is, is it possible to adjust this myself or does a Jaguar specialist need to be involved? If it was a faulty sensor, again is this self-diagnosable / fixable?

Will try manually locking the car as a temporary measure.

Jaguar steve

3,369 posts

95 months

[news] 
Saturday 18th September 2010 quote quote all
piefacemate said:
TurricanII said:
battery voltage dropping? Do you get a couple of brief waring messages about traction control/abs when starting up too?
I've not noticed anything of the such, but then I've not been looking specifically for it! It flashes all the lights as it does it's start-up diagnostics and the airbag light stays on the longest... but other than that...

I'll make a point of checking next time starting it up.

Jaguar steve said:
It might be you have a faulty detector or could be nothing more than currents of air moving around inside the cabin or swift temperature changes triggering the ultrasonic movement detectors.

The sensivity of the detectors is adjustable using the Jaguar WDS. Dispite the sensivity being set to low mine still does trigger the alarm occasionally if locked remotely - particurlarly if the car is in hot sun then goes into shade.

If you physicaly lock the car using the key rather than the remote fob then the alarm is set without the movement detectors being armed. Try this for a while and see if that makes any difference
Thanks Steve, that does make some sense as I moved the car from a cool underground carpark above ground in direct sunlight when it first did it.

I don't know what the Jaguar WDS is, is it possible to adjust this myself or does a Jaguar specialist need to be involved? If it was a faulty sensor, again is this self-diagnosable / fixable?

Will try manually locking the car as a temporary measure.
WDS is the Jaguar diagnostic system on a laptop - it plugs into the diagnostic socket in the drivers footwell and is used for reading codes diagnosing faults and adjusting settings. I'm not sure what its capabilities are regarding diagnosing the difference between a genuine alarm trigger or a faulty sensor 'tho.

You could try just replacing the sensors on the off chance that's the problem I suppose - I'd thought about doing so on my XJ - but decided it was a waste of time and money and just lock it with the key and unlock with the fob now.
Advertisement

Piersman2

4,043 posts

84 months

[news] 
Saturday 18th September 2010 quote quote all
My last 2003 XJR used to do something similar, eventually managed to track it down to a dodgy bonnet sensor. But in the 2003 you get a message telling you which sensor is triggering, can't remember if the X308s do that?

Anyways, one 2" piece of wire sorted the sensor out, I just bypassed it.

Alarm never went off at all hours after that.


melhookv12

517 posts

59 months

[news] 
Sunday 19th September 2010 quote quote all
The ultrasonic sensors are only active when you deadlock the car, i.e double press the remote. Try just locking it with one press, that will tell you if the fault lies within the ultrasonics or something else.

melhookv12

517 posts

59 months

[news] 
Sunday 19th September 2010 quote quote all
Jaguar steve said:
piefacemate said:
TurricanII said:
battery voltage dropping? Do you get a couple of brief waring messages about traction control/abs when starting up too?
I've not noticed anything of the such, but then I've not been looking specifically for it! It flashes all the lights as it does it's start-up diagnostics and the airbag light stays on the longest... but other than that...

I'll make a point of checking next time starting it up.

Jaguar steve said:
It might be you have a faulty detector or could be nothing more than currents of air moving around inside the cabin or swift temperature changes triggering the ultrasonic movement detectors.

The sensivity of the detectors is adjustable using the Jaguar WDS. Dispite the sensivity being set to low mine still does trigger the alarm occasionally if locked remotely - particurlarly if the car is in hot sun then goes into shade.

If you physicaly lock the car using the key rather than the remote fob then the alarm is set without the movement detectors being armed. Try this for a while and see if that makes any difference
Thanks Steve, that does make some sense as I moved the car from a cool underground carpark above ground in direct sunlight when it first did it.

I don't know what the Jaguar WDS is, is it possible to adjust this myself or does a Jaguar specialist need to be involved? If it was a faulty sensor, again is this self-diagnosable / fixable?

Will try manually locking the car as a temporary measure.
WDS is the Jaguar diagnostic system on a laptop - it plugs into the diagnostic socket in the drivers footwell and is used for reading codes diagnosing faults and adjusting settings. I'm not sure what its capabilities are regarding diagnosing the difference between a genuine alarm trigger or a faulty sensor 'tho.

You could try just replacing the sensors on the off chance that's the problem I suppose - I'd thought about doing so on my XJ - but decided it was a waste of time and money and just lock it with the key and unlock with the fob now.
You see Steve, if you use the key and only goto the lock position its putting the alarm into the first stage, if you goto the unlock position then the lock you deadlock the car, ( second stage ) which arms the ultrasonics.

Jaguar steve

3,369 posts

95 months

[news] 
Monday 20th September 2010 quote quote all
melhookv12 said:
Jaguar steve said:
piefacemate said:
TurricanII said:
battery voltage dropping? Do you get a couple of brief waring messages about traction control/abs when starting up too?
I've not noticed anything of the such, but then I've not been looking specifically for it! It flashes all the lights as it does it's start-up diagnostics and the airbag light stays on the longest... but other than that...

I'll make a point of checking next time starting it up.

Jaguar steve said:
It might be you have a faulty detector or could be nothing more than currents of air moving around inside the cabin or swift temperature changes triggering the ultrasonic movement detectors.

The sensivity of the detectors is adjustable using the Jaguar WDS. Dispite the sensivity being set to low mine still does trigger the alarm occasionally if locked remotely - particurlarly if the car is in hot sun then goes into shade.

If you physicaly lock the car using the key rather than the remote fob then the alarm is set without the movement detectors being armed. Try this for a while and see if that makes any difference
Thanks Steve, that does make some sense as I moved the car from a cool underground carpark above ground in direct sunlight when it first did it.

I don't know what the Jaguar WDS is, is it possible to adjust this myself or does a Jaguar specialist need to be involved? If it was a faulty sensor, again is this self-diagnosable / fixable?

Will try manually locking the car as a temporary measure.
WDS is the Jaguar diagnostic system on a laptop - it plugs into the diagnostic socket in the drivers footwell and is used for reading codes diagnosing faults and adjusting settings. I'm not sure what its capabilities are regarding diagnosing the difference between a genuine alarm trigger or a faulty sensor 'tho.

You could try just replacing the sensors on the off chance that's the problem I suppose - I'd thought about doing so on my XJ - but decided it was a waste of time and money and just lock it with the key and unlock with the fob now.
You see Steve, if you use the key and only goto the lock position its putting the alarm into the first stage, if you goto the unlock position then the lock you deadlock the car, ( second stage ) which arms the ultrasonics.
I've never tried the two different locking methods using the key or remote on any other car then my own 2000MY UK spec car so it may well be there are market or model year variations to comply with legislation and some cars are fitted with tilt sensors for example others are not, all influencing how the security systems work.

I had a problem with the alarm sounding repeatedly at more or less the same time of day when I first bought my car. It happened virtualy every time when my (dark red) car went into shade after a long period parked in the sunshine at home, never on dull or cool days and never when parked anywhere else either.

I got Mrs JS to sit inside whilst I repeatedly locked and unlocked alternating between using the key and remote. Every time using the remote either by double press deadlocking or normal locking set the movement detectors and instantly triggered the alarm when any movement was made inside the car but dispite repeatedy trying movement when locking with using the key did not appear to. Prior to doing this I had the sensivity of the detectors set to low but this made no difference.

All the OP can do I guess is try to see how his car is configured. It may well be there was a random alarm fault like a sticky switch that coincidentally cleared itself on my car at the same time as I was experimenting with the alarm or the couple of hard resets I did at the same time too may have done the trick. I know I've never actually proved the sensors are at fault but 5 years have passed without a single false (to my knowledge - I'm sure the neighbours would tell me otherwise yes) alarm since I started locking up with the key, so although I'd never claim to have fixed the problem locking up with the key certainly seems to have got round it.

piefacemate

Original Poster:

592 posts

56 months

[news] 
Thursday 30th September 2010 quote quote all
Great diagnosis guys, and many thanks to all who responded.

Been using the key to lock the car for a week now and haven't had the alarm go off. Not really an ideal situation, having the alarm partially disabled to get around the problem, but is certainly preferable to upsetting all the neighbours!

To everyone who's investigated having this repaired: What's involved? Are we talking a replacement of the sensors or just adjustment of the sensitivity? Does anyone have an indication of costs?

Cheers,

Chris

Jaguar steve

3,369 posts

95 months

[news] 
Saturday 2nd October 2010 quote quote all
piefacemate said:
Great diagnosis guys, and many thanks to all who responded.

Been using the key to lock the car for a week now and haven't had the alarm go off. Not really an ideal situation, having the alarm partially disabled to get around the problem, but is certainly preferable to upsetting all the neighbours!

To everyone who's investigated having this repaired: What's involved? Are we talking a replacement of the sensors or just adjustment of the sensitivity? Does anyone have an indication of costs?

Cheers,

Chris
Sensivity on mine took seconds to adjust via the WDS laptop - you can choose what level you require - but going on the lowest settings made no difference to the number of false alarms I was having so either the system just can't cope with rapid cabin temp changes which I'm sure was the cause in my case or somthing is wrong with the alarm system on my car.


Reply to Topic