akash4393

I have a 2007 525i with iDrive Professional and I have been observing that the battery drains overnight. iDrive gives me the "Transmission Malfunction: gear can be engaged without depressing the brake" and the self takes a while to start the engine. Going through some posts on bimmerfest and 5series.net I reached the conclusion that it might be the battery so I decided to pop it out and get it checked. The mistake I made was taking it to autozone right after driving it for a few miles, so they found the battery to be fully charged and in good health.

I also tried to check the voltage through the obd hidden menu. The battery voltage was somewhere around 12.4 to 12.5. It went down till 11 when starting the engine. After that the alternator kicked in and the voltage went all the way up to 14.1 (fluctuating between 13.9 - 14.1 with changing load).

As a side note I have been doing some coding and have made some changes like enabling pathway lighting, comfort close, traffic info, welcome lights, etc. Although I believe this should not have anything to do with the battery circuit.

I wanted to know if any of you have been through something like and have any insights. It would be really helpful to me as I really don't think I can afford another trip to the dealership anytime soon. I have just changed the aux fan, 6 coils and spark plugs and a $200 component of the coolant pipeline in a time span of one month

Zinger

Hi guys
Please let me know if you fixed your fault and how did you fix it? I think I am having same issue on my car.

Cheers

akash4393

Hey Zinger,

Here is the thing, I was running out of options and did not receive any comments here so I just took the battery out for one night. The idea was to see if the battery is faulty or if my car is eating up power overnight. The next day I just reconnected the battery, cleared the error memory and that was it. It has been running fine for the last two days now. I spoke to my BMW guy and he said that sometimes all your charging circuit needs is a nice power reset, I still find it hard to believe that the solution could be as simple as "have you tried turning it off and on again", but being in IT has taught me that sometimes this is all you need.

Anyways the thing is I haven't seen that dreadful transmission malfunction message yet (touch wood) and the car seems to be starting normally. I will keep you posted if it comes back.

Good luck!