2001 S80 T6 Siren Module 9452709 Replacement/Repair - How To Topic is solved

Post by **cn90** » 30 Apr 2022, 17:52

I am now wondering if it is better to run the 2 wires to engine compartment and keep the 7.2V battery there.
It makes replacing the battery a snap.

Post by **cn90** » 09 May 2022, 20:24

I posted update on ebay battery ($10.95) in S60 forum as below...

NO need to drill the rivets or play with the security bolt if you remove the right HL assembly, it is much easier this way!

viewtopic.php?p=600337

Post by **cn90** » 10 May 2022, 15:11

- Before: "Alarm System Service Required"
- Changed the alarm siren Battery using info in this forum 7.2V, 320mAh Ni-MH type. I did not disconnect the battery in the trunk.
- After: yesterday was OK, but today, it is a different message "Alarm Triggered, Check Car". Does anyone know what this means and how do I reset this message?

PS: I have DICE and VIDA laptop...

Post by **cn90** » 10 May 2022, 21:50

According to this youtube video, if you see message "Alarm Triggered, Check Car", then lock/unlock the car 3 times, this should get rid of this message...

Post by **packetfire** » 12 Jul 2022, 08:38

The alarm module is perhaps more easily removed by removal of the passenger-side headlight assembly (which requires partial removal of the front bumper-cover plastic and the plastic bracket with the tightening clamp that tightens up the bumper cover to get at the 10mm bolt that holds the headlight at the corner of the headlight assembly furthest from the radiator.

Complete removal of the alarm module did NOT harm sunroof operation on a 2004 v70, but this may be year/model specific, given the large number of anecdotes that removal does disable the sunroof. Once replaced with a new battery, I continue to get random "alarm triggered" messages, and neighbors will find the car sitting in the drive, flashing its emergency flashers, but I unplugged the siren, so the car is at least silent.

I guess I need to verify each door's sensor for "locked" and the tilt sensor. Are these something that can be read with VIDA? I sure hope so!

Simayy · Post by **Simayy** » 08 Dec 2025, 05:18

I want to add my experience. I had UEM error sunroof communication fault. No error codes related to siren but it has never gone off and the light does not blink when locked. I've had my mechanic replace it with a siren I found for 25 euros at the scrapyard, and supplied him with the 6 rivets (4 and 2, search for mudflaps) for the RH F wheelwell front mudflap. After this I locked/unlocked through keyhole three times to reset the UEM. Immediately after that the sunroof started working again. The siren does not yet seem to work, perhaps it has been coded removed, I do not care at this time as there are much nicer cars around. Great and cheap fix, total cost 100 euros.

wch2032 · Post by **wch2032** » 11 Dec 2025, 18:48

Recently my alarm module went out. I went and pulled 5 siren units at the junkyard and only found one with a good PCB, everything else had bad corrosion on the boards. The one in my own vehicle had a mostly good board except for one corner where the PCB mask was corroding off. This is such a bad design but at least parts are plentiful. I've relocated my battery to the ECU box, but I don't see myself using this car longer than I expect the battery to last

Removing the bumper is the way to go. Lifting the car is always a pain

How are people sealing the alarm module boxes?

Cees Klumper · Post by **Cees Klumper** » 04 Jan 2026, 13:15

When I bought our 2002 T6, in 2010 with only 40K miles, it had the "alarm system service required" warning (in French, this was in Geneva) upon startup. A few years later, maybe 2015, I bit the bullet and for something like $150 bought a brand new Volvo siren and installation kit from Skandix in Germany. Installation took maybe 2 hours and it's been perfect since. Don't know whether Skandix still sells the kit.

Had a similar issue on a 2008 C70 that destroyed batteries due to a defective alarm module. Replaced that also with a new one and problem was solved.

jelcoward · Post by **jelcoward** » 31 Aug 2026, 23:06

Great write up - thank you. Having had the sunroof get stuck in the open position, I seemed to have resolved the issue by pulling the siren module fuse....but then months later it got stuck again....I think it may have even opened itself but I am not sure. So...I bit the bullet and followed your guide to removing the siren module....which has now seemed to fix the issue again - thank you! The battery was rotten in the siren unit, with its connecting wires corroded off. The circuit board is not too bad - so I have cleaned it up with some electrical cleaner and I _might_ replace the battery (I saw them on ebay as I recall) and reinstall the siren unit......although car theft or a 2004 XC70 here in Vancouver BC is not all that likely.
I haven't reinstalled pop rivets pending making my decision on re-furbing and reinstalling the siren module - the wheel arch liner seems to hold in quite well (it has some clip like mechanism (just lugs really) that slide on to something above it - just look for them on the top of the wheel arch liner).

I am posting to offer a couple of small additions to your write up.
1. There is a youtube video of a fella showing how the siren module can be accessed by removing the front bumper and right hand headlight rather than drilling out the rivets in the wheel arch liner. I was going to go that way _but_ I thought removing the headlight wipers might be a high risk procedure with the small, likely corroded nuts. The wheel arch access route proved fine and easy to do - folks need some steady drilling screws and a bit of caution not to over drill but the rivets are so soft most folks could do this.

2. Disconnecting the connector from the siren module - I struggled with this - it is hard to get a good look at it and I wasn't clear from your description as to how to press the in the retaining clip mechanism....so for others that might run up against this....push it _in_ towards the body of the connector or, in other words towards the left hand side of the car - and the connector should then easily pull out. Photo attached.

3. Removing the anti-tamper bolt - mine turned easily with vice grips so I would try these or pliers as a first approach.

4. To remove the siren module with its bracket, my bracket had to be rotated upwards a small amount to free part the bracket that fits through a hole. It then slid out backwards as you describe.

That's all I've got

Thanks again!

: How to release the connector for the siren unit.; PXL_20260829_230245086.png (484.53 KiB) Viewed 1305 times