Curious issue I have here. I noticed that my tail lights, and tail lights only, were pulsing on for one second and off for one second. This, of course, depleted the battery.

However, I wanted to see if there was an issue that was present on the dash without starting the vehicle - so I put my key in the ignition and turned the key to the first position. When placed in the first position, I received the SOS code beep - high pitch, twice in succession. (... --- ... / ... --- ...) and then the battery finally died out after the SOS beep finished playing the second time.

I've called two Volvo service departments, neither of them have ever heard of these SOS beeps. I called Volvo Cars America and there is no SOS beep in any of their documentation. I don't have international calling, or I'd contact Volvo Cars Sweden (I tried, it doesn't work).

Has anyone here ever experienced, or at least heard of, an SOS beep from the S80?

 

Your alarm siren module might be bad. Have you tested it? The back up battery in them corrodes and damages the internal circuit board. (and there are no beep codes but some electronics can make dying noises as power drains to close to 0 volts)

(with a fully charged battery) Roll drivers window down. Turn off, exit and lock car. Wait 5 seconds. Pretend to break drivers window, reach in and open door from inside. Does the alarm sound and the lights flash? If not, something's broken. Probably the siren module.

If you don't want to replace the module (it's plug and play) you can simply unplug it (after you get to it under the right fender) You might still get a alarm service warning after that every time you start the car.

 

That's an interesting thought. The alarm module is known bad, I don't lock my doors, otherwise the battery drains. I have a multimeter on order at Napa, it'll be here in the morning - so I'm going to do a parasitic draw test on the car.

Is it possible that the alarm module would be able to cause a parasitic draw even though it's not activated?

 

yes, I have seen that and replaced many siren modules for “alarm lights flash at random times and my battery dies “

 

Very interesting. I haven't noticed any flashing lights in my multiple years of ownership - not even the red light on the dashboard.

I'll start with the draw test and see if there even is a draw, then move on to the alarm module. I spoke with someone at IPD that suggested it, could possibly be, the central electronic management system. Which, I looked up the cost of a replacement for that and, I really hope it isn't that.

 

You will find that testing for a parasitic draw on your car will be very difficult/frustrating due to all the modules that turn on and off when you make any change -

I've only successfully tested for a drain on a newer system by using a non-contact (inductive) ammeter. Any method where you disconnect the battery (to install the ammeter in-line) is very frustrating.

And certainly a battery drain could be caused by the CEM (common symptoms courtesy of xemodex) - that would not necessarily explain your weird noises (unless those only occur right before the battery goes dead - when the voltage is very low)

 

Do you think it would be worthwhile to test for parasitic draw on common things (at least on other makes and models) - like the security system and radio, at the least?

This is the first time I've seen the lights or heard the noise before the battery has died, this is the second battery that I've had in the car (first came from first owner, aged out after about 6 months of ownership, this being the second and having 3.5 years on the battery may be making it weak, but once the car has been jumped with a jump box or the battery removed and charged, it holds charge until overnight parking).

 

1. No, most modules on that car will do things automatically like - turn the inside lights or trunk lights off if left on unintentionally.

2. Have you tried disconnecting the battery when you leave the car for overnight parking and seeing if the battery will still start the car the next morning (after reconnecting it of course) ?

 

1. Fair enough, I suppose I'll cancel my multimeter order at Napa... Although, I could use that somewhere else, so I'll just go ahead and get it.

2. Actually, I haven't. I pulled the battery last night after the SOS beeps and put it on a charger/maintainer so, that if it was a parasitic draw, the battery wouldn't be further damaged. The battery does test good, though.

 

With a resistance load tester after sitting for 8 hours? (The kind of tester that heats up when the load switch is turned on, sometimes called a Carbon Pile battery tester)

Example of cheap load tester below

 

that I use for testing batteries. I picked that up after it turned out to be the alternator, not the battery, on my fiancée's Explorer.

But, I didn't test it yesterday - I tested it in December before we went into the cold spells that we've had. However, it'd been fine (without draining) until yesterday morning and yesterday evening with the lights and SOS beep - my charger also reads all battery cells as good, as it's charged now without any error lights.

 

So an update, I tried to do it a lazier way by pulling the fuse for the alarm module - I have a problem there though, the fuse for the alarm module isn't installed.




That's an interesting problem.

 

Yes fuse 38 is missing - but the siren module is still connected to the CAN network - that signal goes to the sunroof module (if equipped) then to the Uem (in the rear view mirror) - you need to unplug the siren - at the siren.

 

It looks like I have a project for tomorrow!

Let me ask - would the faulty alarm module make my sunroof not operate as intended (which is to say not at all) plus prevent my captive touch... thing, on my trunk not work and require a key to open it every time?

 

1. Yes a bad network signal from the Siren module can make the sunroof not function properly.

2. The trunk release usually has a problem - with the switch - under the rectangular rubber pad is a simple microswitch - unless there is a broken wire in the harness that bends with one of the trunk hinges (saw that in many s60s) Do all the other things function back there? (tag lamps, electric lock) Using the key is a purely mechanical way to release the latch.

 

Yeah, everything else functions as intended except the touchpad to unlock the trunk.

And that's excellent news about the sunroof if it works again once I disconnect the alarm module.

 

Just wanted to give an update - I've finally gotten over my upper respiratory infection, and it's been warm enough for me to mess with this.

I disconnected the security module, and my sunroof works again. Trunk lid does not. No warning lights on the dashboard and, so far, the battery isn't draining (it has set on a charger and maintainer this entire time).

Thank you for your help!