Random power issues with my 2009 x5 i48

[davejofcc]

I️ was excited to get my first bmw. I’ve only had it 6 months, and I️ am starting to have problems. Rear air bags are going bad, and every few weeks the dash board lights up like a xmas tree. Abs failure, tranny, etc. I️ pull over the car, shut it off. It won’t restart, but as soon as I️ jump it, fires right and is fine for a unknown amount of time. This has happened 4x in the last 2 months. I️ just replaced the battery and took it to the dealer, they are telling me I️ need a ibs cable to start. The negative side of the battery was completely cover with built up. Any ideas. Mileage is 106k. I️ hope I️ didn’t make a mistake in buying it. Thx


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[BevMW]

Given you know the battery connection is covered in corrosion, give it a really good clean with a wire brush and maybe some chemicals and see how it goes? Have read some other posts where this fixed problems. Battery issues cause havoc on these cars. I may be wrong, but it’s usually caused by a bad battery. If it is that badly corroded that you cannot clean it, replace the end connection.
It most likely will be this dodgy connection that is causing all of your errors, fix this and the see if anything comes back before paying for any parts.

Also, when your battery was replaced, make sure it was coded.

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[thesamiest]

This most definitely can be caused by a bad battery. Had all these symptoms. But they can also be caused by a whole lot of other things, in your case it sounds like its the battery so start there.

[Skyline]

Who installed the battery? Was it coded? Your car has a "smart" alternator that charges based on the age of the battery. If it's not coded, it can screw things up and quickly ruin a new battery. What is meant by "coded", is that the car must be told that a new battery was installed, and what the CCA of the new battery is; as correct batteries for this car can vary a bit in CCA.

Go to an autoparts store and get a battery terminal brush. This has two ends; a female wire brush that fits over the terminal post, and a male end that fits inside the battery cable clamp. Remove the cable, clean both ends and reinstall. Ideally, hook up a battery saver device or jump pack to the car while the battery cable is disconnected so you don't lose you personalized settings. If you have white corrosion around the terminal, this can be neutralized with a combination of baking soda and water.


Once both things are done, if it does not clear up your problems, you need to start looking for other issues. Next step is to get both the battery and alternator tested by someone who has a sophisticated battery / electrical system tester; like a Snap-on EECS750:

https://store.snapon.com/Electronic-...m-P823717.aspx

Confirm that the battery is still good, and the alternator is charging properly. Often a failing alternator will be working, but just not putting out the correct voltages all the time. These tests must be done by someone who is familiar with these cars. This is NOT like a car from your youth where an alternator could be tested by removing a battery cable while the car is running to see if the car stalls....we're in a whole new world of sophistication with an X5; or any modern BMW for that matter. Either an improperly charging alternator or a battery that's not holding its charge can cause a low voltage situation that will cause all sorts of wacky issues in an X5. The fact that you've had to jump the car on multiple occasions is NOT a good thing. Every time a battery gets run down to the point that you need a jump, it never comes completely back (unless it's a marine type battery).

[Mflara420]

Originally Posted by Skyline

Who installed the battery? Was it coded? Your car has a "smart" alternator that charges based on the age of the battery. If it's not coded, it can screw things up and quickly ruin a new battery. What is meant by "coded", is that the car must be told that a new battery was installed, and what the CCA of the new battery is; as correct batteries for this car can vary a bit in CCA.

Go to an autoparts store and get a battery terminal brush. This has two ends; a female wire brush that fits over the terminal post, and a male end that fits inside the battery cable clamp. Remove the cable, clean both ends and reinstall. Ideally, hook up a battery saver device or jump pack to the car while the battery cable is disconnected so you don't lose you personalized settings. If you have white corrosion around the terminal, this can be neutralized with a combination of baking soda and water.


Once both things are done, if it does not clear up your problems, you need to start looking for other issues. Next step is to get both the battery and alternator tested by someone who has a sophisticated battery / electrical system tester; like a Snap-on EECS750:

https://store.snapon.com/Electronic-...m-P823717.aspx

Confirm that the battery is still good, and the alternator is charging properly. Often a failing alternator will be working, but just not putting out the correct voltages all the time. These tests must be done by someone who is familiar with these cars. This is NOT like a car from your youth where an alternator could be tested by removing a battery cable while the car is running to see if the car stalls....we're in a whole new world of sophistication with an X5; or any modern BMW for that matter. Either an improperly charging alternator or a battery that's not holding its charge can cause a low voltage situation that will cause all sorts of wacky issues in an X5. The fact that you've had to jump the car on multiple occasions is NOT a good thing. Every time a battery gets run down to the point that you need a jump, it never comes completely back (unless it's a marine type battery).

You hot the nail, right on the head. I replaced just the alternator voltage regulator plus a new battery and my problem is gone.

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[ard]

1. OP stated he already replaced the battery.

2. Dealer diagnosed a bad IBS.

3. Bad IBS is a known issue.

4. OP has disappeared.... must be an urgent and pressing matter.

5. Google "how to replace the IBS sensor/cable".... Faulty IBS sensor and negative battery cable replacement - Bimmerfest - BMW Forums