Alarm constantly goes off

[kyle9]

My only other guess is that the battery is critically low, but not low enough to trigger a low battery warning on the vehicle's HUD. It has been my experience with BMW platforms that they are absurdly sensitive to low state of charge, and they tend to spit out all sorts of bizarre and inexplicable behaviors when the battery is low or dying. I mostly have experience with Hyundai, Suzuki, and Toyota vehicles, but I've never in my life seen those brands match the level of weirdness that BMWs put off when the battery is dodgy.

Many people have come through here with electrical gremlins, swearing up and down that it's not the battery. But it always seems to be the battery.

I’ve had this issue too. One of my Supra just sits in my garage all the time and when the battery gets low the alarm starts randomly going off.

Keep a trickle charger on it and no issues (I literally never drive it)

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[climhazzard]

I’ve seen a handful of reports of this behavior on BMW forums due to rodents inside the cabin triggering the motion sensor. Hopefully that’s not your issue, but you could try temporarily disabling the motion sensor and see what happens.

I echo razorlab’s recommendation to pull codes; it should provide direction.

 

[ggrelish]

I tried with the motion/tilt sensors disabled and the alarm still went off.

There were no codes when I scanned with my obd2 scanner, so I'm going to take it by the dealer tomorrow and see if they can scan. I'll update if I get an answer.

 

[sup.dc2]

i noticed mine would go off when it's locked and a window is cracked open. some anti theft thing. so i just never crack my windows anymore

 

[razorlab]

There were no codes when I scanned with my obd2 scanner, so I'm going to take it by the dealer tomorrow and see if they can scan. I'll update if I get an answer.

What OBD2 scanner? Those are usually generic. Which is why I mentioned using Bimmerlink or Protool.

 

[FLtrackdays]

I tried with the motion/tilt sensors disabled and the alarm still went off.

There were no codes when I scanned with my obd2 scanner, so I'm going to take it by the dealer tomorrow and see if they can scan. I'll update if I get an answer.

Careful with Toyota dealers. Not all are created equally.

 

[ggrelish]

Dealer said the alarm never went off with them. They scanned, no codes. They of course thought it was the jb4 even though I told them it hasn't been plugged in for a few days. Got the car back, parked it, locked it, alarm went off within 20 minutes.

 

[J29DB03]

The dealer you took it to, was it the same one you bought it from?

 

[ggrelish]

I bought it used, but I've had it for about 4 months before this problem ever started.

Another thing I've noticed is that the car doesn't beep anymore when I lock or unlock the car. I'm pretty sure it did before I started having this problem. I don't know if it's related, but thought it might clue someone in to my overall problem.

 

[razorlab]

I bought it used, but I've had it for about 4 months before this problem ever started.

Another thing I've noticed is that the car doesn't beep anymore when I lock or unlock the car. I'm pretty sure it did before I started having this problem. I don't know if it's related, but thought it might clue someone in to my overall problem.

Sounds like the car might be having an issue going into deep sleep. When I had that issue, my lock/unlock beep also stopped working.

When you lock the car, does the rear view mirror light blink rapidly at first or just a normal blink?

 

[Tsuki8]

Its me guys, ive been pressing his alarm through the app. ? (Its a prank, i swear?)
(the infotainment hasn't been reset and previous owner still paired, maybe...)

 

[ggrelish]

Alright, here is hopefully the final update, and I will update the first post with the whole saga and fix in a couple of days once I confirm this fixed it.

I got Bimmerlink as a user suggested, and it showed 2 errors in the Roof function center:
DE8C5E: LIN: Sine doesn't answer
801A55: Theft alarm system: Alarm- details in alarm memory.

I didn't know how to get into the alarm memory, but I searched the codes and it seems like there are some BMW owners with similar issues, with the likely culprit being the alarm siren.

I ordered the replacement part:
Toyota part number: 89040-WAA02

I couldn't find the part anywhere except for California, so I took the part out of my car to see if it was BMW made and it is.
BMW part numbers:
65755A83298 (old)
65755B61723 (new)

It was out of stock everywhere. Toyota ended up getting it to me the quickest. The new part from Toyota actually had Toyota branding this time, not BMW, but it appears the same, obviously.

The part is located under the driver's side rear quarter-- take off the back bumper and the plastic part under it.

Once I got it installed and everything put back together, I now have the chime back when I lock/unlock my car, so I am 97% sure this was the fix. I'll drive it tomorrow to clear the codes and leave it locked to see if the alarm goes off again. But I am pretty sure this is the fix.

 

[concept]

I'm curious if the part has been upgraded, since it has a different part number. The other part of this question is for what year was the change made.

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