BMW alarm keeps going off randomly


Updated Tuesday Feb 13, 2018


BMW alarm may go off randomly for no apparent reason. The alarm will often get triggered when the car is parked and there is no one in or by the car. This problem can affect BMW 1, 3, 5, 7, X1, X3, X5 and other series. If your BMW alarm keeps going off the problem is often caused by a stuck or defective BMW hood switch but it may also be caused by any of the following. 


Hood Sensor

The hood sensor on BMW can trigger the alarm to go off. The sensor may fail at unpredicted time triggering the alarm. The hood sensor is located in the engine compartment.

bmw hood switch

Replacing the sensor is a simple DIY project. As a temporary solution, you try unplugging the hood sensor.

bmw hood button switch causing random alarm keep going off

This will stop BMW alarm from going off randomly but you will get HOOD OPEN warning message in the instrument cluster. You can buy BMW hood sensor online for any model.  

Interior & Tilt Sensor

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 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. 

Dead Battery

In a few cases, an 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. If your BMW battery is over seven years old, it may be time to change it anyways. Follow this guide on how to change a BMW battery yourself.


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Approximate mileage at the time of problem.