Alarm going off / parasitic power draw

[TriggerFish]

Totally possible, yes. I have had this before (a faulty amp causing battery drain) on an e46 (same electrical system), and also know if you disconnect the battery with the alarm armed, the alarm will sound

So yes, battery voltage dropping will trigger an alarm

 

[paddy wright]

I was going to say this will be a battery issue- fully charge the battery or replace it and the issue should be resolved including the key remote working again. I had this on mine even though the old battery was on a trickle charger it was not ever fully charged. New battery solved the issue.

 

[Nellybauer]

Battery is less than 6 months old. Was replaced not long before I bought the car, i guess someone replaced it thinking it was the issue before I bought the car.

Using suggested techniques to identify parasitic drain of putting a multimeter in series to the battery, I've found the car even long after it should have gone to sleep keeps drawing 0.4A / 400mA. Whereas an expected draw should be under 50mA.

Checking fuses, I seem to have around 150mA draw through fuse 45 which is marked as for the airbag. However pulling that fuse I still measured a draw of 400mA from the battery. So I'm now struggling to work out where the draw is coming from!

Any suggestions welcome!

 

[BumpyZ4]

Battery is less than 6 months old. Was replaced not long before I bought the car, i guess someone replaced it thinking it was the issue before I bought the car.

Using suggested techniques to identify parasitic drain of putting a multimeter in series to the battery, I've found the car even long after it should have gone to sleep keeps drawing 0.4A / 400mA. Whereas an expected draw should be under 50mA.

Checking fuses, I seem to have around 150mA draw through fuse 45 which is marked as for the airbag. However pulling that fuse I still measured a draw of 400mA from the battery. So I'm now struggling to work out where the draw is coming from!

Any suggestions welcome!

Do a voltage drop check on each fuse instead of amp draw. When you pulled the fuse you probably woke up another module on the network.