The alarm system is a complex system on this vehicle and I would recommend you actually take it in to BMW for proper diagnosis. You need BMW's special equipment to look at some basic paramaters to see what is causing the alarm to set off. It was complex enough that BMW put a service bulletin out for some parameter checks and start fault tracing from there. Here is the service bulletin.
SI B 65 42 07
Audio, Navigation, Monitors, Alarms, SRS
Alarm Triggers Unexpectedly - Troubleshooting
All with DWA Alarm (Option 302)
When troubleshooting a customer complaint that the DWA (Anti-theft alarm system) triggers unexpectedly, stored fault codes may be misleading and result in an incorrect repair.
The first check must be to check the alarm counter, which shows the component responsible for the false alarms and the alarm frequency.
The alarm counter is checked using the BMW diagnosis equipment as follows:
MOST bus vehicles: "Function selection/Complete vehicle/Body/Locking and security functions/Burglar alarm system/DWA activations".
I-bus vehicles: The input responsible for alarm triggering is stored in the alarm memory in the ZKE (General Module). The alarm memory can be read out with the "short test" or with "read fault memory" in the diagnosis program.
Continue troubleshooting based on the results from the alarm counter check.
So as you can see at this point any type of advise given to try and replace "this component" or "that component" would be a waste of time and money. If going to the dealership seems pricey you should look for a BMW specialist shop where that is all they work on. There labor rate should be much less then the dealership but I can not say it would be the same for the parts you may need since most likely the parts will be dealer only.
Saturday, February 12th, 2011 AT 3:47 AM