activating volumetric alarm sensor
 

Hi all,

I retrofitted one of the later square BMW volumetric alarm sensor units (the one that is located near the center of the headlining) but I can't get it to actually work. I followed this guide here and is definitely wired up correctly: https://www.the75andztclub.co.uk/for...d.php?t=118740

When I lock the car I can hear the alarm sensor making clicking sounds similar to rear parking sensors, but no matter how long I wait after locking the car (should start working after 20 seconds) the sensor isn't setting off the alarm when I'm moving about inside the car.

I have 2 sensor units and have tried both in case one was faulty. I have the exact same problem when I tested one on my typhoon years ago.

Does the volumetric alarm need activating on a t4? I can't see any option to activate it on toaf.

Cheers
Rick

Ultra Sonic Alarm.
 

Hi Klazy,

There is a sub-section in the SA part of our cars ZCS codes for alarms.

My car is coded for “Alarm No US”. I am guessing, but think the “US” is MG Rovers abbreviation for “UltraSonic”.

If this is the case, I think you will need to calculate the value for “Alarm WITH US [ultrasonic] and make the necessary adjustment (difference between "No US" calculation and that of "WITH US] to your ZCS via your T4.
Regards,
Bruce.

I can see what's confusing you. The how to tests the alarm before any T4 involvement and reckons a T4 is only required to bring the alarm under the diagnostic umbrella. Probably worth contacting Russ or one of the other T4 bods to clarify it.

Think you'll need to change the coding to activate it, as it enables those inputs/ outputs in the BCU.
From memory it's easy to do as it's in the dealer options page in vehicle configuration ;)

Russ

When I installed mine it worked straight off, no T4 needed. Could be an age thing i.e. dependent on when the car was built?