It is one of several things:

1. The motion sensor is out of adjustment,
2. The tilt alarm is out of adjustment,
3. You bonnet sensor is out of alignment,
4. Your battery is weak and triggering a low voltage condition.

It could also be your doors/boot, but presumably you'd see the lights remaining on in the car after you close the doors.

Trying disabling the motion / tilt alarm by pushing the lock button 2x. That will at least narrow it down!

d-

 

My money is on the motion sensor, maybe dirty or obstructed.

As DouglasABaker said:
Trying disabling the motion / tilt alarm by pushing the lock button 2x. That will at least narrow it down!

 

Had a similar problem and many others have too - in many of our cases it is the hood sensor...see post #4

http://www.m5board.com/vbulletin/showthread.php?t=102558&highlight=alarm

 

Thank you guys for your continues support. I parked my car that day on incline. And had the sun shield in front glass + the battery is weak as from my last service the dealer noticed that when he started up the car. I will have to check which one did cause the problem.

Thanks again guys

 

Did you leave someone locked in the car?

 

Check to make sure the hood (both sides) are completely closed.

 

Having the same issue as the OP since yesterday and I am following the advice in this post. Will keep you updated if something different turns out to be the cause.

 

Should have posted this months ago, yes it was the hood sensor, a $20 part and self install.

Interesting that my 540i is 3 years older with twice the miles and the original part (same as the M5) works fine!

 

As stated above, the hood sensor is a major culprit for this, mostly if you live in a hotter climate. My alarm was going off randomly during the daytime only as the temps started heating back up here in South Florida...sure enough, yanked that hood sensor out and all is quiet. The system thinks the hood is permanently closed so your alarm is satisfied.

Got a new sensor on order, it's about $15:
BMW #61314158205

good luck! :cool2:

SP

 

Interesting in that we have just had two 92F humid steamy days. I did jiggle the hood sensor and also dusted around the motion sensor and it has not gone off since.