V70: Electrical VIDA Reading off alarm cause - help!

[Stu B]

Hi All,

Just a quick one, I'm sure this is user error but I'm sleep deprived from my alarm going off at 1am and waking me up....

I'm trying to diagnose why my V70 occasionally flashes it's hazard lights in the night, and then last night sounded the alarm. It doesn't show on the dash that the alarm was triggered, shows no 'alarm service required' message, or flag any DTCs in VIDA.

I did some searching and can see how you use VIDA to 'read off alarm cause' in CEM / advanced so tried it quickly at lunchtime. However, I just get this screen with no further options when the posts I've read indicate I should get an activation to run and bring back the last few alarm trigger reasons.




Anyone done this recently and able to confirm please? I've tried double clicking, restarting VIDA, ignition off and on but always get this screen rather than the VCT2000 icon to click and start the process. VIDA works fine in all other aspects as far as I can tell.

I suspect the alarm siren battery of course, but would like to confirm it's not something else first before I remove the SCM fuse for the night....

Thanks!
Stu

[cheshired5]

I changed my siren in 2014 when the car was 12 years old so it's difficult to see beyond a failing siren battery being the cause.

My hazards would flash with no siren noise then sometimes the siren would sound all at the same inopportune moments in the middle of the night.
The system also became incredibly sensitive to above average air temperature/air pressure changes so a cold night following a warm day or an impending thunderstorm at any time of the day.

No Vida error codes either.

I can't say 100% that your siren needs changing or at least splitting open to change the battery but I also wouldn't spend time investigating any other reason for the erratic behaviour when the battery is 12 years old.

[Stu B]

Thanks for the reply, makes sense. I did read a few posts saying the siren going off in the night on colder nights as you mention was a factor and it certainly seems to be.

The neighbours across the street reported the hazards flashing to me but no siren so it does seem to add up and as you say, it’ll be the original 2009 issue battery in there.

I’ll see if I can get the siren out, I believe it’s in the scuttle on this model rather than under the wheelarch. If I can’t find it today then fuse 26 seems like it’ll stop the racket for this eve anyway!

I’ll report back

Cheers
Stu

[ilmiont]

That screen is showing you the alarm cause - Interior Motion Sensor (IMS).

I do recall it looking different when I did this last summer on my S60, although mine's a P2 so may well be different data in VIDA.

That screen suggests all of your recent activations were due to the interior motion sensor.

If you subtract the Alarm Cause 1 time from the Global Time, you get the elapsed time since the last alarm trigger:

4,835,203 - 4,834,456 = 747 minutes = 12.5 hours ... that about right?

[Stu B]

Originally Posted by ilmiont

That screen is showing you the alarm cause - Interior Motion Sensor (IMS).

I do recall it looking different when I did this last summer on my S60, although mine's a P2 so may well be different data in VIDA.

That screen suggests all of your recent activations were due to the interior motion sensor.

If you subtract the Alarm Cause 1 time from the Global Time, you get the elapsed time since the last alarm trigger:

4,835,203 - 4,834,456 = 747 minutes = 12.5 hours ... that about right?

Thanks - that’s interesting and yes it would have been around 12 hours later as I hooked VIDA up approx 12:55pm today and the alarm was acting up around 12:30 - 1:00am this morn.

I was expecting an activation that could be run to show the last few triggers but perhaps the software output varies depending on the specific car model?

[Stu B]

I found the siren earlier and removed it for investigation. It is to the left of the battery under the scuttle panel, a bit of a fiddle to get out.

It’s a Ford part ref: fomoco 6g9n-19g229-de of 2008 vintage so I will have to assume the battery in there is knackered. However, it’s a metal case and doesn’t look easy to open up to check.

It looks like this (quick Google found this pic) so posting a link:
https://volvo.caffynsparts.co.uk/par...-v60-xc60-s60/

Anyone cracked one of these open? Google suggests it’s shared with Mazda, Jaguar and Land Rover so lots of options for spares hopefully.

I tested the alarm without it and guess what, it honks the horn instead!

Cheers
Stu

[george57l]

Originally Posted by ilmiont

That screen suggests all of your recent activations were due to the interior motion sensor.

Just chipping in 'cos I've had the same - several false alarms, mostly silent, but a couple with horn. Over half of them overnight.

And today I had a phone call from Volvo On Call to tell me it had gone off last night (I already knew that!). None of the previous false alarms were registered by Volvo On Call, so I need to get to the bottom of that, too.

Soooo..... I'm interested to know why the alarm siren replacement was proceeded with when it seemed to be an internal motion sensor that triggered the alarm eachtime? Am I failing to understand some part of this?

I'm planning to take mine in to get the dealer to tell me which sensor keeps triggering my alarm (assuming it is the same sensor each time).

I had the same problem many years ago and it was almost certainly some insect activity in the car - probably a spider being nocturnally active. A good clean-out of the car and the problem went away.

So if I know which sensor is triggering, maybe a good hoover around that area might fix this. We'll see. But I don't expect to have to replace a siren unit on a 6 or 7 year-old car.

[ShadeTek]

If the car horn sounds, this means the ECU has lost connection to the siren and as a failsafe, it sounds the car horn, assuming it has been deliberatley tampered with in attempt to disable the siren.

[Kev0607]

Originally Posted by george57l

Just chipping in 'cos I've had the same - several false alarms, mostly silent, but a couple with horn. Over half of them overnight.

And today I had a phone call from Volvo On Call to tell me it had gone off last night (I already knew that!). None of the previous false alarms were registered by Volvo On Call, so I need to get to the bottom of that, too.

Soooo..... I'm interested to know why the alarm siren replacement was proceeded with when it seemed to be an internal motion sensor that triggered the alarm eachtime? Am I failing to understand some part of this?

I'm planning to take mine in to get the dealer to tell me which sensor keeps triggering my alarm (assuming it is the same sensor each time).

I had the same problem many years ago and it was almost certainly some insect activity in the car - probably a spider being nocturnally active. A good clean-out of the car and the problem went away.

So if I know which sensor is triggering, maybe a good hoover around that area might fix this. We'll see. But I don't expect to have to replace a siren unit on a 6 or 7 year-old car.

Maybe not, but the battery in the siren could be iffy & that could trigger the alarm randomly.

[Model flyer]

My son had the same issue with his s60 2010 model . Always went off at night when temp dropped. Fitted a replacement and all sorted.
Opened up old unit all looked well with no corrosion and battery seemed to check out. Think fault developed in circuitry probably age related( built in redundancy ?)