Increaed Battery Dishcharge, Tracing Problem so far Question

[mslopnick]

Hi All,

New to the e90 thread, but have plenty of experiences with E28s and E39s.

Wife is driving an 11' 335xDrive. For about 7 months now. About 80,000 miles. Water Pump etc. replaced at 75k. Car sat for about a week without being driven and now every 2-4 startups, independent of length of time sitting in between, will throw the increased battery discharge light up on the iDrive and console. After driving, message obviously goes away and all is well for another 2-4 cycles.

I tested battery and it's healthy, also tested alternator and it isn't failing.

On a whim I went out the other night after car had been sitting for 4-5 hours and was locked and noticed that the "start button" was illuminated. Nothing else. I hadn't recently locked or unlocked the car and the fob was far enough away not to be interfering.

So, now I'm stumped. When the car is locked, the start button intermittently is lighting up and I'm hearing an servo or "click" under the hood every 20-40 seconds or so. Not a whine, but a mechanical click. I'm assuming this component is awake or not going to sleep and slowly draining battery and giving me the error message, but I'm hoping you all can point in the right direction or ask me some questions that can help me diagnose what it is that is intermittently not turning off and causing the drain.

Thanks,

Mike

[mslopnick]

Update: Took of the vanity cover and the noise is definitely coming from the top end of the engine. Makes me think a servo or something maybe for Valvetronic, but I'm not throwing any codes to point in that direction. Also, that cycling noise is happening every 60 seconds and right after I lock the car.

[White94RX]

The vehicle will stay "awake" for about 15 minutes after you turn off and lock the car. You need to check after that amount of time to see if it still makes the noise.

Second thing, you say your battery is "healthy". How do you know? What did you test it with. Have you run an energy diagnosis test plan? A battery that you think is good, may still be on it's last legs. How old is it? Was it registered properly the last time it was changed?

[mslopnick]

Great questions. I understand the 15 minutes to sleep, thus my explanation of this happening in the middle of the night hours after it should be asleep. I pulled the voltage as the car was started and at the end of a long drive with highway miles. In both instances at startup I was at 12.-- something volts and under load 14. How does one perform a energy diagnosis test plan? Battery and car was pre-owned from dealer, so it's a BMW battery, though I'll check tonight on the Born-on date. What else?

[Codes2]

Our cars are sensitive to battery capacity and voltage, having a lot of advanced electronics.
I've had my batteries test as good (Canadian Tire, cheap machine), and still give me this alert with increasing frequency.
Removing the battery and having it tested for 30-60 minutes (at Part Source) will better expose the decrease in performance.
In my case, I've had to change the batter in two of my E9x cars, even though they started fine. Problems solved. (and do code the car/battery for each other)

** EDIT ** I know this has no bearing on your clicking sound. I can't say I get that with the key fob far away and locked for over 15 mins.

[White94RX]

The energy diagnosis test plan is done with ISTA (BMW's diagnostic software). It will tell you the health and condition of the battery, as well as a lot of other important info, like if something was keeping the vehicle awake.

[jclausen]

How did you test your battery and the energy dx test will tell you a lot. Sounds like the typical under charged battery from poor condition or letting the car sit to much or driving only short trips