Alarm going off randomly

[PAVZ]

Hi all,

Recently the alarm on my 2017 M4 F83 has been randomly going off for no reason.
I think one of the sensors is failing but I would like to know if I would be able to diagnose this myself if I had OBD and used some software like Torque to read the fault data. Would it tell me which sensor triggered the alarm?

I think it is the faulty sensor as normally when I lock the car, the mirror LED supoposed to start flashing slowly, but sometimes I have noticed that for the first 10 seconds or so it flashes rapidly and then goes back to the standard slow flash rate. According to the manual, this may indicate a problem with one of the sensors, but how do I find out which one it is?

Any advice would be greatly appreciated.

[shaolinx]

A OBD device and BimmerLink app are good investment regardless if you plan to keep the car long term. If you want to investigate the problem in detail, you should look into ISTA.

[WordOnRoad]

I'd think #3 and #4 are where you wanna start.

#3is 65759493759 and #4 looks to be 65759233009 based on a quick Google search.

#4 doesn't seem to show up on RealOEM when using LCI F80.

I'm not sure if these are behind the wheel well liner, or inside behind the trunk liner. Either way, keep us posted on what you find. Hope this was helpful.

[PAVZ]

I downloaded the ISTA+ and checked the fault log. I found that I had a microwave sensor fault and it didn't seem to be responding. I have 4 of these sensors in the car, two front and two rear (there is no rear central in my car as far as I can tell - F83 LCI M4 2017, please correct me if I'm wrong).

The rear right one was the faulty one - voltage and temperature readings both behaved in a way that suggested an internal fault.
I replaced the sensor and the readings were all correct - very close to or the same as the other 3 sensors.
I have checked the door and bonnet / tailgate sensors - all indicate open/close correctly.

I reassembled the car and went home with the feeling of a job well done.
About two hours later, the car alarm went off again for no reason.

I disabled the microwave sensors to see if that would make a difference and that seemed to help - no more random alarms, but it bothers me. Is there anything else I can check by myself?