Alarm randomly going off

[Rossi1001]

So when I bought this car (March 2003 E85 2.5 Auto) 1.5 years ago, the previous owner told me the alarm would randomly go off at times, which it duly did. Sometimes later the same day, sometimes two weeks or more later. However after changing the battery a few months into my ownership all seemed well, until today when it's gone off twice, the second time tonight whilst the battery is receiving an overnight charge.

I plugged in my Creator C110 code reader, but I couldn't see anything obvious in the chassis and body sections, to find any alarm fault / trigger codes. Does anyone know if this tool is capable of finding out what's triggering it, or can any other diagnostic tools do this if the C110 can't?

 

[Abbas]

It could be the bonnet alarm sensor thing?

https://z4-forum.com/forum/viewtopic.php?t=21845

https://www.ebay.co.uk/itm/192750615558?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=nrlWAgVYQAq&sssrc=4429486&ssuid=&var=&widget_ver=artemis&media=COPY

On a z4 I bought previously I had this issue. I noticed a connector being unplugged when I was tinkering around. So I plugged it in. And over the next few days the alarm kept going off :rofl: I later realised it was to do with that. It must have been a faulty sensor. I think it thinks someone is trying to open the bonnet and get into the car. Unplugged it again and was absolutely fine. Or you can fit a new one

Could be worth a look

 

[colb]

Don't think the Creator scanners can see the alarm sensors you would need BMW INPA to view them on a Laptop or one of the higher end Tablet Scanners like Autel or Launch that can see and test individual sensors of the system. Sounds like its the bonnet switch on yours, disconnect it or fit a replacement, see if that stops the alarm activating.

 

[coldel]

Bonnet switch. It is 99% of the time the problem, every one gets it.
Just disconnect it tape it up and forget about it.