Volvo S80 2004 Alarm system trouble

[Rucho26]

I own a Volvo S80 2004 2.9l NO Turbo.
And I have two problems with the alarm system on my car.

1. I noticed that when I lock my car OR unlock it (through the remote) there are NO flashing lights what so ever.
2. I had locked myself inside the car on purpose to see if the alarm goes off, when I unlocked the door from the inside and opened the door and the lights started flashing BUT no alarm went off. When I press the panic button on the remote the alarm does go off with the flashing lights.

Anyone here have any idea of how to fix this? Anyone here had this happen? Why is this happening?

Thank you all very much.

[SuperHerman]

Most likely your siren module is going bad. Just responded to a similar post on the XC70 forum.

The module has batteries in it (so it works when the battery is disconnected) that start to leak with age. Usually they last about 7 years. The acid from the battery ruins the internal circuit board. You can remove it and try to repair it or buy a new replacement.

I would start looking at this as your problem.

Module is located on the pass side inner fender under the wheel well liner. On the XC90 I believe you can get to it through the headlight area, once removed, the S80 should be similar. I did it on mine a few years ago via the wheel well liner. It has a special fastener that is problematic to remove. Many use a vice grip and replace it with a standard 10mm upon completion. Look up "alarm module" or "siren module" and you should find plenty of write ups.

I bought a used unit, opened it up, and replaced the batteries. You may get lucky and yours is still repairable. The original one I had was not, but the used one was. On another Volvo I just bought a new module for $250 and plug and played then moved on with no issues.

[Rucho26]

*update*

I made sure the hood closed and the light flashes only once and only when I lock it. Not when I unlock it. And I do have the "Alarm System Service Required" message come up.

[SuperHerman]

I am curious to see if this will work. Try initiating your built in computer test. From what I have seen it has a test of the alarm module. If communication issues with the alarm module are there, it will tell you.

Watch this video for instructions. It should work similar on your car.



or here:



Report back.

[June]

*update*

I made sure the hood closed and the light flashes only once and only when I lock it. Not when I unlock it. And I do have the "Alarm System Service Required" message come up.

Lights flashing only once when arming is normal for the 2004 S80. No chirps or multiple blinking lights when arming on this model. When unlocking with the remote the interior lights illuminate. June

[SuperHerman]

My experience is "Alarm System Service Required" indicates exactly that - and it is the Siren Module. This was the case on my XC90 and S80.

Perform the test and see what the computer tells you.

Here is another link: https://steemit.com/cars/@novaswe/hidde ... -s80-00-07

Although I don't see the siren module specifically listed, I am hoping a related code will be there. Knowing this will help others in the future. Of course VIDA will show the exact problem, but not all have VIDA.

[Rucho26]

I did that, and the results where very discouraging.

Test results:
TCM DTC SET (transmission, I know about this one still need to take it in to a workshop for a faulty valve replacement);
AUM DTC SET (audio, I did install a subwoofer and 2 aditional speakers: so maye this is what is triggering it?);
ECM DTC SET (emission, I do have a hose missing on the engine, runs from inlet manifold to oil trap);
CCM DTC SET (climate, I had the blower die, <I think> and maybe that set it);
DIM READY (Driver Information, board is green <Ive tampered with this a lot, surprised; gave the dashboard a blue color on dials>;
PDM DTC SET (Passenger Door, no idea everything works fine);
SRS READY (airbags, at least these still function);
DEM DTC SET (Diferential Electronic Module, no idea what this is);
REM DTC SET (Rear Electronics, I have the aditional speakers conected in the trunk of the car, this triggered it?);
CEM DTC SET (Central Electronic Module, no idea);
SWM READY (Steering Wheel, Green);
PSM DTC SET (Power Seat, maybe this is why the seat memory position get deleted and have to reprogram them);
DCM READY (Not sure what this is, but I'm glad the board is green on this);
DDM DTC SET (Driver Door, no idea everything works fine).


Maybe I should just get rid of the car. Against my will. *sigh*

[SuperHerman]

The onboard test is only "sorta" useful. A full VIDA (or equivalent level scan) is needed to really drill down.

That said, the onboard test did flag issues that you have an explanation for so it has provided some help.

As for the alarm module, it impacts several systems so fixing it may solve those items. At this point scraping the car for an alarm issue makes no sense - buy a new or used module and install it makes more sense.

At the very least pull the current module and see if it can be repaired.

[jimmy57]

The panic feature of the remote uses the regular horn. The alarm is a wailing siren.

A lot of those set DTCs will not be for an issue that needs attention. The diagnostics on the car detects out of line conditions which do not necessarily mean a fault needs to be fixed. If the battery on the car fails or goes dead for any reason, a lot of codes set for low voltage in many modules. Power seat and both door modules will have DTCs for window or seat switches activated more than a second when the window has reached bottom or top bottom limit or seat has reached a travel limit.
DEM is the unit on front of rear diff controlling power to rear wheels when traction is lost on front wheels even a wee bit.