I recently bought a new BMW 750i with 95k. A few weeks ago I was getting an alternator fault message and a few days later needed a jump to get started. I then bought the alternator. I ended up having to get a second installed because after having my car for a half hour I got the same alternator message. The guy at Monro Muffler replaced it at no cost and said my battery was good. He said I was running at 14v at the time. Since then (12/5/16) my car has given me a battery fault message every time I wanna listen to the radio without the car running. Also coming out of work, the car wouldn't start but as soon as I opened the trunk and the battery compartment to jump the battery, the car electronics kicked in like it never shut down. It happened again this week (12/19). I was driving to work and while in Drive, the car shut off in the middle on the road. No lights. No interior messages. No hazards! I called AAA to tow but someone offered to jump me in the meantime. I opened the trunk and battery compartment again and the car kicked back in again without jumping the car. I started the car and drove it home. I haven't used or started it up since 12/19 but did run it today. I received all sorts of fault messages and checked the voltage on the hidden menu, I was running 8-9k volts.

I'm wondering if the need for a new battery would cause me to shut off completely while in drive. Also why would everything start right back up without jumping the battery just by opening the trunk and battery compartment.

Any help would be greatly appreciated. I really don't want the stealership playing trial and error with my finances.

 

I need experienced help please!!! CAN ANYONE SOLVE MY ISSUE?

I just recently bought a BMW 750i 2006 w 94k. I've owned it for a month now and have had electrical failure three times. 12/3/16 was The first time I received an "alternator fault" code and tried to start it up coming out of the store and couldn't without a jump. I then went to Monro Muffler and got a new alternator, they said the battery was good. I didn't have the car two hours before I received the same message. I took the car back and was given another alternator which was completed on 12/5/16. I have not received the alternator message since. However if the car is not running and the radio and other electrical items are running I will immediately receive a "recharge battery" message.

On 12/9, coming out of work, new alternator installed I wasn't able to start the vehicle. No lights, etc. It wasn't until I went to jump the battery, opened the trunk and the battery compartment that the cars lights bells and whistles booted up without a jump. Everything ran fine until 12/19. I was driving to work and the car shut off while I was driving down the road. I no power. No lights. No hazard lights. I called AAA for a tow and while waiting someone offered a jump. I opened the trunk using the key and the battery compartment and the car booted back up again as if it never shut down.

I'm in desperate need to know what is going on as I know that going to the stealership for their trial and error at my expense is not a road I want to go down. Has anyone else had this experience? I thought I was upgrading my driving experience getting a BMW but I'm starting to second guess my purchase. Previous threads seemed to point to the IVM but I don't know what that is or what it controls. Please help!!!

 

I merged your topics .
PLEASE STOP MAKING MULTIPLE TOPICS ON SAME SUBJECT !!!

 

I merged your topics .

PLEASE STOP MAKING MULTIPLE TOPICS ON SAME SUBJECT !!!

My apologies. I wasn't aware of the forums etiquette.

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sounds like a bad negative cable or bad connection from the alternator or battery

 

Can I check those things without an electric shock risk or is there some tool that I should use?

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Try disconnecting the battery sensor . Or maybe could get any electronic modules in the trunk some water from rain , also there is a module hardly hear called ivm module . That should be together in the engine /trans computer compartment. Give it a try and check the small fuses .

 

I started it up today and used the hidden menu to monitor the volts. It operated just fine. 13-14v consistently while running. 11v when the car wasn't on but using heat radio MP3 transmitter etc. never shut down. All wires were secured. All small fuses are intact. I considered the ivm module but wasn't aware of how to determine if it's bad based on a visual test. Any knowledge on that?

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Sounds like a loose power line or contact. Intelligent battery sensor is one common problem
Às well the battery or the alt. I had a similar problem before and I unplugged the + cable from the battery with the engine running ( some people say it's bad or no accurate ) but it was the fastest way to detect for my alt or battery in my previous e60 545i and the e65 . Also make sure that all electronics works as they should . For example if CD changer works randomly it could discharge the battery even if not playing CDs or overnight if you used the car early.

 

I'll look in to the Intelligent Battery Sensor and will also try to disconnect the positive cable while it's running as well. I don't stand to damage anything if I do that do I?

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When it shuts down it's been 30 degrees and 9 degrees. Today it's 55 and running fine. I'm not sure if that plays a part but I'm trying to find something consistent.

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I heard that even though it looks fine from outside there is something inside that burns or something. Try any junk yard . Or some friend that have a similar car . Have you tried disconnecting the intelligent battery sensor and drive around to see if it's shuts down again? How old is that battery? Also by the fuses in the trunk should be a hidden button like to save energy or something. Don't know what it's really for. But a friend somehow moved it to the off position and he was getting all kind of messages . Later we released to the original position and you can heard a sound when all electronics come alive . Like if that was restricting power to each module. To me is more the cable from the battery is having issues with those sensors .

 

That makes me suspect on the battery itself. I currently have that issue with my 745 sometimes when it's really cold it cranks but kinda slow until the engine fires. But if I let the car unlock overnight the next day in the morning it won't start I know it's the battery since it has a sticker from AutoZone from 2012 . And it's a bit smaller in size and CCA ARE LESS than what it should have (850 at least )

 

The document I attached may help you.

 

Also I had checked the hidden menu when running and it gets between 13.1-13.9 sometimes hits 14.2 but as soon I power engine off without pulling the key out it starts dropping like a clock and after a minute it's almost dead. Check for the door lights when engine is off after you run it and if the courtesy lights blink could be the battery isn't keeping enoought charge.

 

http://www.bimmerfest.com/forums/showthread.php?t=842864

 

Thanks for this link. I'm going to try this this week.

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I'm inspecting the battery now. It was mentioned it should be at least 850 cca and the battery currently in the car is 765 but would my car shut off going down the street because the battery isn't sufficient once it cranks up?

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Mine has the same . I think the alternator has being trying to compensate or better said overcharging itself to don't let the car sit down. That's why if running the car with electronics on it dies . The battery it's too low for all the electronics it has to had ready ( at the moment you want to use Heather , a/c radio, navigation, etc) even though you don't have them on but it still consume some electricity. And remember aftermarket batteries after 3 years start giving problems . That battery is what an E46 uses to give you an example . 6cilinders engine and not too many sensors and things to keep asleep for the driver to use when needed.

 

The alternator thinks the battery doesn't hold a charge and doesn't get higher then 765 and keeps pushing it . My guess is that because if the battery not the right size amps the IBS sensor won't read more than 765 CCA and it ended with pushing to it's limits your alternator as thinking your battery is draining and at some point the system decides to better shut off to let the alt or even the battery rest . I'm wondering if the battery was hotter then normal .

 

Thanks a bunch for your insight. I was hoping someone could assist with this.

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I see. I can tell that the battery isn't for my vehicle because even in the pics it doesn't fit the bracket brace well. I'm going to get a new ivm and new battery since the alternator has already been replaced and let you know how everything turns out.

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Kool. And good luck.

 

Ivm