Alarm triggers when unlocking (occasionally)

[acpstunts]

This is getting rediculous now, and embarrassing. Unlock the car this morning at my house no problem. drive, go stop to get breakfast, come out, unlock, alarm goes crazy. This has been happening on and off for about a year now.

So I read the hood switch is a faulty piece, np, unplug it, but issue still occurs.

I read also the battery can be the issue, but again this has been happening on and off for about a year. Ive noticed no issues with the battery (Ill triple check today when i get home). But its a newer deka battery. Also if it was the battery, wouldnt it trigger after sitting for some time, not me getting breakfast and coming back 2 min later.

Im just ready to pull the plug on the siren piece and call it a day. Anyone else having expierenced this? What did you end up doing to solve it.

thanks!

[LVP]

I had happen once or twice, but I chalked it up to sticky alarm buttons. That being said, I could not press a remote button to deactivate it. Only turning the key forward in the lock did it. Maybe my remote battery is toast or the buttons sticky. I was going to try that after I got through the mechanical nuances first.

[lhordmclain]

Mine got fixed by RR the hood switch...

Do you have BMW specific scanner to help pin point the erroneous alarm issue that you are having?

I'm subscribed to this thread, curious to learn the final resolution.

[Qsilver7]

Do check the vehicles battery voltage...because if it is dropping below 11.89 volts (which is 0% state of charge)...then it may not be recharging the internal battery inside the alarm siren...which could be the reason for the false alarming.

If you're checking the battery's voltage using OBC TEST 9...make sure that you wait at least 2 hours after turning the engine off so that there's no residual surface charge from the alternator...and try using ignition position 1 (instead of position 2) when running TEST 9 because only a few control modules are activated in KL R (ignition position 1 aka RUN)...whereas ignition position 2 (KL 15 aka ACCESSORY)...all control modules are activated...thus a larger drain on the battery.

Also...OBC TEST 9...when the engine is running...you're looking at the alternator/charging system's voltage. With the engine off and ignition in position 1 or 2...you're looking at the battery's voltage.

Take note of the DWA red LED (clown nose) below the rear view mirror. You can tell if one of the monitors is remaining open when you initiate the alarm.

See the chart below...and if you are getting the rapid flash then it settles down...there's a monitor remaining open:

[acpstunts]

Firstly thank you for all that information! Very usefull. I actually wasent even aware of the on board testing. So I went outside and i got into Test mode. Test 1,2,3, etc but was having issues accessing test 9. Once on test 9 how do you enter it? I would hit the left button on the cluster and it would say Lock: ON and that was it.

[Ricky Bobby]

You have to unlock the OBC first.

[acpstunts]

how do you do that. Like i said never really touched these tests before.

[acpstunts]

nvm found a write up on it. thanks. Will report back with results.

[acpstunts]

Well just checked the voltage out and it is indeed at 11.8v which would determine that the siren alarm battery is not being charged properly.

[LVP]

Mine was intermittent. I replaced the hood switch and haven't had an issue since (it's been about 3 months now).