A common problem BMW owners may face is the car alarm going off at random times or in the middle of the night. The alarm gets triggered when the car is parked, there is no one near the car.

In this guide, we go over some of the most common problems that cause BMW alarm to go off or for no apparent reason.

If your BMW alarm keeps going off the problem is often caused by a stuck or defective BMW hood switch. The most common solution that will fix this problem is to replace the BMW hood switch. This problem can affect BMW 1, 3, 5, 7, X1, X3, X5 and other series.

Symptoms

  • BMW Alarm Goes Off Randomly
  • BMW car alarm when the car is parked
  • The alarm may go off in BMW even when no one is near the car

Common Cause

bmw alarm going off randomly due to bad hood switch

If you are getting a hood open warning message on the dashboard or your BMW alarm goes off randomly the most likely cause is a defective BMW hood switch.

Another common location for the BMW hood switch (bonnet switch or sensor) is near the driver's side strut tower.

To fix alarm going off you may need to replace the BMW hood switch.

This video shows you how to replace the BMW hood switch.

Temporary Solution

disable bmw alarm sensor by disconnecting it

Disable Sensor at Locking: When locking the car using your key fob, press the lock button (BMW logo) twice. This should disable the input from the hood sensor and other external sensors. Note that this may make it easier for someone to break into your BMW.

Disconnect the sensor: Disconnect the sensor or placing the tape on top of the hood sensor will prevent the BMW alarm from going off randomly but is not recommended the solution.

Warning - By disconnecting or disabling BMW alarm sensors the alarm system will not go off if someone tries to open the hood when the vehicle is locked.

Possible Problems

Interior & Tilt Sensor

bmw interior tilt sensor causing bmw alarm to go off

Some BMWs are equipped with interior motion sensors that detect motion inside the car. There is also a tilt sensor that monitors the movement of the vehicle. The tilt sensor's purpose is to detect thieves who may try to steal the car, steal your wheels or tow the car away without permission.

The interior sensors may not work properly in situations when the car is parked in congested garages. It may detect movement outside the car. It also may not work properly if the windows are open.

The interior sensor on BMW can be disabled by following this procedure.

Lock vehicle using keyfob remote. > Within 10 seconds press the lock button again. > Lights will flash. This will turn off the tilt alarm sensor and interior motion sensor.

Low Battery Voltage

wear bmw battery causing alarm to go offAn older car battery can trigger the alarm to go off as well. If the battery voltage drops below 9 volts the alarm may go off randomly. Battery voltage can drop for two main reasons:

  1. Battery is old
  2. The car has a parasitic current draw when parked

If your BMW battery is over seven years old, it may be time to change it.

Further Troubleshooting

If you have replaced the hood switch and the battery and your alarm will still go off, further troubleshooting is necessary. Complete a full system scan using a BMW scanner and examine the fault codes present.

Diagnosing BMW problems with Foxwell for BMW scanner. There are many scanners that are capable of reading and clearing BMW fault codes.

We hope that you found this guide on how to troubleshoot the BMW alarm going off randomly helpful. If you have any comments or would like to report an alternative solution use the comment section below.

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Visitor
Member since 2020-07

I have a 2002 BMW Z3 Roadster. My alarm will go off on its own for no apparent reason. Sometimes when I'm casually driving down the street, sometimes when its just sitting out in the garage by itself. When I'm driving it will go off, stop for 10 seconds and do it again over and over. Which fuse can I pull just to turn off the alarm?

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Visitor
Member since 2020-07

I've been having the exact same issue with my e92 m3. I've been searching and just can't get it figured out. Have you had any luck?

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Visitor
Member since 2020-07

I have a 2018 BMW X2. Tonight while I was driving home the little red light on the rear view mirror started blinking. And all of the sudden the alarm starts going off. It would stop the alarm sound for a about 15 seconds and then come back on the driveway red flashing light never stopped. What could this be besides a pain in the butt?

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Visitor
Member since 2020-07

I have a 520d F10. Alarm keeps on going off randomly. sometimes i get a "discharged when stationery" message when i jump into the car. I have put a new battery a few months ago and still the same problem.

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Visitor
Member since 2020-07

My 2004 bmw 530ii key fob does not work so I cannot stop the alarm or operate doors. My dashboard lights are off and car cannot start

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Visitor
Member since 2020-07

Hi i have a bmw e90 323i, the alarm comes on when car is locked but wont stop if i press the remote, it can be opened using the manual key to open the drivers door but thats about it... no lights and wont accept the key in the ignition.

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