XC60 alarm issue but not the siren?

[surfslammer]

Hi, any advice on this one please.
XC60 R Design AWD 2014

I have the alarm service required message appearing constantly with every start now. It was previously intermittent. Having read a number of posts, it seemed the usual siren unit would be the likely suspect. To be fair, the siren unit was corroded, and I have swapped it for a second-hand replacement which appears to be working.
I still have the error message.

I have the following observations:
• A friend (electronics whizz) has checked and tested connections and voltages etc. and all seems to work fine on the replacement unit.
• The remote key sets the alarm with the indicators flashing, the mirrors closing and the red alarm light on the dash flashing all as expected.
• The remote key disables the alarm with all the expected indicator flash etc.
• There are no false alarms triggered.
• When using the remote to lock the car/set the alarm, then opening with the blade key, the alarm triggers and the siren blares out as expected.
• When using the remote to lock the car/set the alarm but remaining inside the car, the alarm is not triggered by movement (the reduced movement guard was not enabled).
• The movement sensor on the roof interior seems to be firmly in place and no visible issues.
• There are no obvious other issues occurring.


I’m no tecchy but wondered if any of you guys have any pointers as to what the likely issue is and what other checks I can do?

Any advice much appreciated.

[jamesmccann]

HI Surfslammer,

I believe that after you replaced the siren (if it is suitable) you need to have the message cleared by someone who has Vida, hope this is of use to you.

[surfslammer]

Originally Posted by jamesmccann

HI Surfslammer,

I believe that after you replaced the siren (if it is suitable) you need to have the message cleared by someone who has Vida, hope this is of use to you.

Thanks for the reply. I understand that may clear it.

However, would that account for the movement sensor appearing not to be working?

I am trying to get an idea of possibilities and if I can, try some cheaper fixes before heading to the garage. A second hnd movement sensor isn't that expensive if that is a likley culprit.

[Chrisv60]

The message doesn't need clearing, it will go away once the issue is fixed. However, Vida or a professional reader will pinpoint the issue. I paid an auto electrician £30 and it said the batteries were faulty. My money's still on the siren unit.

[scbamber]

My similar problem showed up yesterday too... But unlike the OP I have only seen the message twice in 6 months. It certainly doesn't keep showing every day, and seems to clear itself. This thread now has 3 users with a 2014 car!! Mmmm.

MY2015 D4 V60 owned since new in Dec 2014, averaging 700 miles/month. Twice in six months the warning ‘Alarm system service required’ has displayed on starting the car for the first time in 3-4 days, but did not reappear at the next engine start an hour later after a 30-mile drive.

Knowing from this Forum that the electrics on these VEA models can throw up strange warnings if the charge on the main battery is even a little low, I replaced the 8-year-old original main battery with a decent Varta one 15 months ago as preventive action before the winter. I have usually charged the battery overnight every 3-4 weeks in the winter, not least as I normally have the heated seats and aircon on all the time in the colder months.

I am not concerned that the siren/alarm battery might be on its way out as I probably wouldn’t bother to get it or the siren unit replaced. The alternator voltage is fine, and no other warnings come up for any other glitches. Could it be a parasitic drain somewhere draining the main battery a little over a few days of not using the car, but just enough to trigger the warning? Or does the Panel have any other thoughts?

[surfslammer]

Originally Posted by Chrisv60

The message doesn't need clearing, it will go away once the issue is fixed. However, Vida or a professional reader will pinpoint the issue. I paid an auto electrician £30 and it said the batteries were faulty. My money's still on the siren unit.

Thanks Chris. A Vida diagnostic will be my next step to hopefully pinpoint exactly what is casuing it. I am 100% it is not the batteries in the siren though. I'm hoping it will be something as simple and cheap.

[surfslammer]

Originally Posted by scbamber

My similar problem showed up yesterday too... But unlike the OP I have only seen the message twice in 6 months. It certainly doesn't keep showing every day, and seems to clear itself. This thread now has 3 users with a 2014 car!! Mmmm.

MY2015 D4 V60 owned since new in Dec 2014, averaging 700 miles/month. Twice in six months the warning ‘Alarm system service required’ has displayed on starting the car for the first time in 3-4 days, but did not reappear at the next engine start an hour later after a 30-mile drive.

Knowing from this Forum that the electrics on these VEA models can throw up strange warnings if the charge on the main battery is even a little low, I replaced the 8-year-old original main battery with a decent Varta one 15 months ago as preventive action before the winter. I have usually charged the battery overnight every 3-4 weeks in the winter, not least as I normally have the heated seats and aircon on all the time in the colder months.

I am not concerned that the siren/alarm battery might be on its way out as I probably wouldn’t bother to get it or the siren unit replaced. The alternator voltage is fine, and no other warnings come up for any other glitches. Could it be a parasitic drain somewhere draining the main battery a little over a few days of not using the car, but just enough to trigger the warning? Or does the Panel have any other thoughts?

Hi scbamber. From reading around the intermittent message to start with is not uncommon. I also read in some posts that the faulty siren battery can be a cause of battery drain. I experienced that but not since the replacement siren with tested battery was fitted. Hopefully I can get to the bottom of my issue and shed some light on it whatever it is.

[surfslammer]

I thought I’d drop by and give an update on this. Having replaced the usual candidate of the siren (which was found to be corroded inside) but still not solving the issue, I went to a Volvo independent to get a fault reading. That came up with the following:

CEM-BD1896 Volumetric sensor – Component Failures – Component internal failure

He said he’d get me a price for a new unit. In the meantime I sourced a use item that evening and swapped it in. That was a simple job of unclipping the outer case on the roof lining, unplugging the old unit and plugging in the replacement. I turned the ignition and the error message reappeared. However, I locked the car whist sat inside and when the alarm set, moved around and unlike before, the alarm sounded. I pressed the fob to unlock the car to stop the siren, turned on the ignition and thankfully there was no alarm service message 😊

The Volvo independent phoned me with a price of £152 inc vat for a new sensor. I got it for £17 and the siren at £23.

Thanks to those who have previously posted about the siren replacement and have given links to video how to’s which made life a lot easier. Replacing the sensor on the roof lining above the back seats is straight forward. Slowly and carefully prize the outer casing off and then it is a fairly obvious unplug and refit.

For the price and simplicity, it may be worth a punt on a sensor if you’ve ruled out the siren. I must have been very unlucky as my siren was definitely dead. The battery had leaked and the circuit was very corroded.