[joshaguirre]

Before clicking off, I would encourage you to please read my issue in its entirety.

So on 8/23 I moved up to my apartment for college and within 15 of unpacking my car, my rear speakers start buzzing loudly and won't stop. I tried everything I could do to make it stop...locked the car, unlocked the car, started the car and tried turning on/off the radio...when I turned the radio on the entire speaker system sounded horrible also. I tried driving the car immediately to see if it would stop it...nothing. I finally just drove back to my apartment and continued to unpack, within 5 more minutes it finally stopped. The issue hasn't came back since and the stereo is functioning normally. I looked up the issue and saw someone said that there could be water in the car near the stock amp, I took a look on my car and the area was completely dry.

Ok, part two on this entire electrical system issue. The next morning I start the car and I get a battery symbol on my dash warning me that apparently my battery had drained significantly. The car also took a minute to start supporting that warning. Since then, when I start the car in the morning, I will get this light and sometimes it will go away fast...sometimes it will take much longer for it to go away. The symbol only comes on in the morning after the car has been sitting for 11+ hours.

I finally grabbed my computer and ran ISTA as well as INPA to scan the car. Besides the random two codes I've had for years I got a new code...9D12 coming from the SINE(alarm module). ISTA suggested there was a "short circuit to batt. +", I believe it's referring to the battery in the siren? I scanned the car while the engine was on and this fault was not currently present. It's worth noting that I actually put in the alarm myself about a year and a half ago, so I'm not sure what to thing.

I'm really paranoid now that if I let my car sit for too long I won't have enough power to start the engine. I also replaced/registered my battery this year which makes diagnosing this issue a lot more frustrating. I'm honestly not sure what in my vehicle's electrical system could both be causing the battery+stereo freak out system. Any help would be much appreciated.

[joshaguirre]

Update: I now suspect the alarm siren is causing the battery discharge warning on my car. Some people claim the code 9D12 means that the internal backup batteries in the siren are bad and should be replaced. I also located the fuse for the alarm system so I'm going to pull it tonight and see if I get the battery discharge warning on my dash tomorrow.

If the warning doesn't happen tomorrow morning then I'm going to attempt to replace the batteries in the siren. What bugs me is that I bought the alarm retrofit kit off ECS Tuning less than two years ago and the siren seems to be giving me problems. This makes me even more not want to buy a new siren from them as the issue could possible happen again. My opinion a part that I bought less than two years ago from them shouldn't be going bad. It's one thing if the siren was on the car since it's build date(2008) and it decided to go bad, sure I'll spend the $200 and put a new one in, but a less than two year old part...come on.

I'm wondering if the siren issue could of possibly caused my stereo to freak out also...I've heard of weird situations on BMWs where one electrical problem can cause many others to occur...

[Three_thirty_I]

I recently had my E90 in for an ongoing intermittent battery drain issue, they found it was being primarily being caused by the alarm siren and angle sensor lithium ion batteries that were dead along with the car's actual battery that was ruined as a result of the abuse (this is was the second replacement battery that was subjected to the intermittent battery draining). So far, car has been behaving! Those lithium ion batteries aren't expensive, so I would just have them replaced if you suspect them.