A few weeks ago, the error message "Alarm System Service Required" came up on my 2005 XC90 2.5T. At the same time, the sunroof (moonroof) stopped working.

Fortunately, there are a number of threads on this topic:
* https://volvoforums.com/forum/volvo-...ck-open-31433/
* 2001 S80 T6 Siren Module Replacement/Repair - Matthew's Volvo Site
* Alarm Service, Alarm Triggered, Sunroof Not Working - Howard's Volvo Maintenance

Thought I'd add my own experience. As others have found, the car alarm module is upstream of the sunroof motor circuit. When the NiMH battery in the siren unit fails, that "Service Required" message will flash and the sunroof motor will lose power.

The quick fix for this XC90 -- YMMV -- was to pull the fuse that controls the alarm system. In my case, that was the #26 10-A fuse located under the steering wheel (easy access, but requires a Torx screwdriver). See page 160 of the Owner's Manual and attached image.

If this works, the service message will go away, and the sunroof motor will be energized.

The permanent solution is to replace the failed siren unit. It is installed forward of the passenger (right-side) front wheel well, accessed by partly removing the plastic fender skirt.

The local dealer quoted me about $300 for the siren. Instead, I ordered part #9499758 from Volvo Parts Webstore, discounted to $232. I also ordered 8 rivets (P/N 979878, $1/ea) for re-attaching the fender skirt; ended up using five.

The procedure is a revision of the one posted at Matthew's Volvo Site, linked above. That's for a 2001 S80, but very similar to my '05 XC90.

Tools & Supplies

Torx T-25 screwdriver to access fuse box
Drill and +/- 3/16" bit
10 mm socket/wrench
5 to 8 Volvo rivets (above) or 3/16" X 1/4" pop rivets
Rivet gun
6 mm x 1.0 hex bolt, ~1 cm long. Replaces anti-tamper mounting bolt
And typical items from your toolbox

Procedure

De-energize the alarm system. Do this by disconnecting its fuse (described above) or by disconnecting the car's battery.

Jack up and block the passenger's side (right) front wheel. Remove the wheel.

Remove the two nuts (10 mm heads) and drill out the aluminum rivets holding the fender liner to the fender. It may not be necessary to remove the liner entirely; see attached image.

Look up into the front part of the wheel well to see the siren inside its mounting bracket (red arrows in attached images).

Remove the anti-tamper mounting bolt. I used a pair of small Vice Grips (see image).

With the siren removed, use a slotted screwdriver to depress the locking tab on the wire connector, then slide the connector out.

Replace the old siren with the new one.

Test the repair: Replace the #26 fuse or re-connect the car battery. Turn on the ignition. Clear the error messages (button at tip of stalk). Check to see that sunroof works. Roll down driver's window and lock car with remote, activating alarm system. Wait 5 minutes, till alarm is active (alarm-system red LED beneath windshield is flashing 1x/10 sec). Reach in window, unlock door, open door -- that should trigger the siren. De-activate alarm with key and again clear messages.

Replace fender skirt, using rivets.

Replace wheel.

 

Adding trackbacks to previous VolvoForums posts on this topic ("Alarm System Service Required" and sunroof/moonroof stops working).

 

Does the computer need to be updated to recognize the new siren.

 

I bought a used 2006 XC90 V8 which displayed the error message "Alarm System Service Required" everytime its engine was turned on when the doors had been locked before entering the car(I reset the message everytime). The sunroof worked properly when I bought the car and did not show any problem until three years later, when it stopped working entirely, stuck in the closed position. I had not bothered to have the "Alarm System Service Required" message problem fixed before but the sunroof malfunction really bothered me. So, I tried removing the fuse as suggested by AMac and, in my car, it did NOT fix the sunroof problem. The dealer said that I need to replace the "sunroof control module" and, if I wanted to take care of the "Alarm System Service Required" message, I have to replace the anti-theft siren. They are talking about $500 in parts plus labor.

 

I would say it's the alarm module inside the RF wheel well behind the right front headlight. Fairly easy to DIY.

 

Follow on the posts about the "Alarm System Service Required" and the sunroof malfunction: first I had the sunroof control module replaced by the dealer and it did not work initially. The dealer mechanic had to isolate the alarm siren wiring which was interfering with the sunroof control module. After that it was necessary to download a piece of software into the XC90´s computer. This fixed the sunroof problem, but not the "Alarm System Service Required" message. Next I had the anti-theft siren replaced by the dealer, (the siren is located where CedarBear explained above). However, I would not venture to DIY because it was necessary again to download another piece of software into the XC90´s computer. Finally got rid of the message and the anti-theft siren is fully operational! I wouldn´t advise to DIY unless you have the hardware to download the software necessary to make these parts interact with each other. It looks like it was designed so that the dealers can make more money!

 

Correct. With DIY, sunroof will work again, but dealer software is required to get rid of 'Alarm System Service Required' message.

 

I replace the alarm siren module on my S 80 and now I am unable to start the car. I have tried to reset the computer by locking and unlocking the car 3 times and also disconnecting the car battery and nothing works. I hope I do not have to tow the car to a Volvo dealer and have them reset my computer.
thanks

 

Interesting thread, but in my case, yes, the alarm siren doesn't work, but no service warning ever came on? Removed and checked #26 fuse and still no sunroof, so is there other places to look for problem? So has anyone replaced module or switch, but both operations do not work. Usually is switch goes bad, one or the other operation would fail, so any suggestions.

Thanks,

 

Hello Volvo Forum, I am new to forums and hope that I am posting my message in the right place and will get a helpful response.
I have a 2005 Volvo XC90 that has a "Alarm system needs servicing" message.
I have replaced the Alarm module under the passenger side fender with a factory new module, but the message still comes on. The dealer said that replacing the module should have solved the problem and nothing needs resetting, but it could be something else. The sun roof works and all fuses check good. What else can I check to solve this problem?

 

Did you happen to verify if alarm system worked prior to replacing module? I have found that wet CEM module can cause many false warnings, one being alarm needs servicing. Does the alarm work, did you try it? May sound silly, but many have wasted money replacing things Volvo computer message says is wrong, a real money maker for Volvo. lol

 

I have a 2005 xc90 T6 that I recently purchased used a little over a month ago. The moonroof wasn't working but appeared to be closed all the way. I could hear air blowing through it while driving. I just assumed it was a bad seal and\or maybe the fuse or motor went out. I also had the "alarm system service required" notification on the dash. I didn't think much of it since I've had several cars before the a "check engine" light on and had no issues with. I up until yesterday hadn't bothered much to look into either issue considering my car wasn't having any issues running or driving. Well, my car was filthy from road grime and mud from winter so I decided to take it through the carwash. I was sitting there as it started just enjoying it when all of a sudden my moonroof started gushing water and I'm soaked. Thank goodness it wasn't one where you are locked into a track. Not knowing what to do and how to stop it I put it into gear and fled out of the carwash. I was in a panic. Turns out the wind I was hearing was the moonroof open just a tiny bit. So I went and bought a set of fuses thinking that replacing the moonroof one was the problem. Sadly, that didn't fix it. So I did some research and stumbled across forum after forum linking the moonroof failure to the faulty alarm system. Looking for ways to fix it I initially found 2 options first was to replace the alarm module which would have been a nightmare to get to. Option 2 was to take it to a dealer to have the alarm system permanently shut down. I don't live anywhere close to a Volvo dealership so that wasn't an option. I looked at one more thread and saw I could remove the fuse for the alarm system and it might possibly fix it. So when I pulled the fuse I noticed it had blown. I put a fresh fuse in there and magically my moonroof worked and my warning message was gone!!! I was dreading having to replace the motor but that wasn't needed. I'm so happy it was a quick and easy fix. I love my XC90 and would hate to shell out hundreds of dollars to possibly get it fixed. On a side note I discovered that that car has 4 fuse panels!! My husband told me he was proud of me for looking into the issue and resolving it myself. He had planned to look into it This weekend.

 

Hello everyone,
I am having an issue with Sunroof not working based on the outside temperature, it works when it’s cold and stops working when its hot outside (above 70F). Very annoying to say the list.
Reading the treads here they point to Alarm system. My alarm woks fine in either condition Hot or Cold and no “Alarm Service Required” message is displayed. When the Sunroof stops working I also loose Rain Sensor,Reading lights on the Roof console, vanity mirror lights. So, logically this points to something in the electrical circuitry that “expands” when it’s Hot and cutting the 12V supply to the Sunroof.
If this happened to you and know something, please give me a hint ?.
I have tried the Hair Dryer trick heating up UEM (Inside Rearview mirror), Roof Console, Sunroof module, grounding points, CEM module; NO LUCK. Off course done this when is cold outside and things working as they should, just trying to find where the voltage supply is cut when Hot.
I have VIDA and it is very helpful in troubleshooting but no luck so far.
If you know a specific test that I could do to uncover this issue let me know?.

Thank you in advance.

 

I found my dash security diod blinking but alarm silent on ocassion, then found that my vehicle battery was running down.
I bought a new battery when it wouldn keep a charge overnight. Then i found it was still dropping voltage and a "light went on in my head" that the alarm system module must be the related.
I read up on the alarm and found the battery in the alarm system eventually leaks and thats prolly where my battery is dissipating from.
I pulled the alarm fuse and no more battery bleed.
Later I found that my sunroof switches were not responding but surprised that the sun roof had another fuse than the alarm system- so here i learned that they are related. I found a used alarm online which may buy me sum time. Soon will find out if all my issues go away or if i still get dash notices about the alarm. I plan to multitool cut around the old alarm edge and see what the status is of the battery is and if it can be "rebatteried" . If I return the rebatteried old unit to the car maybe I wont see the dash notice???? Stay tuned. may take a couple weeks as other parts of my life need attention too.

 

On my 2006 S60 I was having the typical Alarm Service System Required. After reading a few threads I ordered a new battery for my alarm siren. I wasn't yet aware of the corroded circuit board issue. I pulled my alarm siren out, cut it open to replace the battery and found the circuit board corroded. Remembering one thread that talked about just unplugging the siren and not having the alarm but allowing the sunroof to work. With the siren out of the car I started the engine, no light and the sunroof works! I think I'll put it back together and roll with it.

 

thanks for the follow on info. I bought a used siren on *bay and will get around to installing it soon. I figured the batteries in the original siren leaked and ruined the siren IC board. Im gonna use my multitool to cut around the seam of the old siren and see the situation inside. I really miss my sunroof. Interesting that you were able to get the sunroof working just by unplugging the siren cable.

 

I just took the car for a ride and everything works, keyless entry, sunroof, no warning message. I understand also no siren, but I'm ok with that.

 

I had several inches of rain get in the car. Slowly all the electrical functions have returned as the car dried out except for the power to the moonroof and the alarm error message. Is it possible that it all will resolve with time to dry or is this coincidental to the water?

 

Did you check the fuse for the alarm/sunroof??? it might be fried from sunroof saturation. Also if I assume water got backed up in your drain tubes from the sunroof maybe the switch got compromised??? prolly need to inspect the sunroof switch. Did you used a pneumatic hose with a nozzle to try blow out the tubes?? I had to do this on our jetta sunroof as it clogged .

how is your battery doing ? if the back up batteries in the siren box ( right forward fender about 2 oclock above liner looking at it from side of wheel well) shorts, the battery will bleed out as a clue that the siren box has shorted. I bought a used siren on *bay but it only lasted about 6 mos. obtained a NEW siren "kit"(including fender liner rivets) on e*uoparts for $50 less than a stand alone siren. go figure.

hope that helps

 

I hope you understand that the carpets in your car are not "flat". There is as much as 4 inches of foam rubber glued to the bottom of the carpets. They will never dry on their own once wet. If you don't remove them and dry out the 4 inch sponges - shortly your car will mildew badly. Usually it's failure of the front sunroof drain tubes what allows water into the passenger compartment.

When the siren module has a problem it can disrupt the CAN bus signal to the sunroof module, causing the sunroof not to work.