Dead Battery
 

Hello all.

In my V8 4.4 I received TRANS FAILSAFE message and now my battery is dead.

Is it safe to allow AAA to come replace the battery and then take the truck to the dealership to have the batter registered?

Should I just have the truck towed to the dealership?

I read something about a memory card or stick.....what is this and is necessary?

Pros and cons to allowing AAA to replace the battery?

you posted in E53 forum, so i would assume that you have an E53. There is no need to register a battery in E53, just make sure the battery is of a correct size- there are many battery threads on this forum. I would suggest an AGM battery in the maximum permissible size (you have a V8), and I am not sure if the AAA will be able to change the battery, as it is located in the trunk, under the spare tire, and requires some light disassembly to gain access.
Once the battery is replaced, you might not need a tow to a dealer, as the FAIL SAFE message might have been secondary to a failing battery. On the other hand, if the original battery is relatively fresh, you might have a current leak - but first things first...

Get the battery replaced.

start the car

if car starts up, drive it for about a mile or so

if you have no more messages, just keep on going on with your life...

you should not spend more than $150 for an AGM battery - I bought one from Advance Auto parts for about $120 with online coupon

Thank you Terminator X, this was very helpful!!!

Ditto TX...unless you have an e70 or F15 X5...there's no need to "register" your battery because your X5 was designed BEFORE the BMW engineers came up with the IBS (intelligent battery sensor) and the communication BUS system that measures/tracks the alternator/battery/DME.

The main thing to make sure "someone else" does is...double check that they hooked the battery up to the vent tube.

The battery class size you need to shop around for is the 49/H8 or 95R/H9 battery. A battery in either of those 2 class sizes will have the specs to power your X5. The latter (95R/H9) is a slightly larger more expensive battery...for those who need the extra power for additional electronics that may have been installed.

Here's a link to a reply yesterday about battery replacement:

http://www.xoutpost.com/1014162-post13.html

Another tip is you can change the battery with the car running and it wont hurt anything...that's what I do. That way you wont loose any memory settings.

I had an Decka AGM in the car when I bought it...it did not last long. I have a battery specialist shop near me that just tests and installs batteries and he told me to only use the lead acid with the vent tube in my 02 4.4.

I have NO IDEA why.....The AGM will not hurt anything...it may be longevity I have no idea.

I have AGMs in all my motorcycles and think that's the way to go but again have no idea why he said no to a AGM on my E53.

QSilver7, thank you. You and TX were both absolutely correct. I called BMW and they confirmed the information that you provided.

I was able to call AAA and they provided an H8 battery. The battery and installation was $140.00.

As you noted QSilver7, I was able to make sure the tech connected the vent tube to the new battery. Thanks to Youtube videos (LOL), I was a where that this should happen and exactly where it was.

The car is running just fine and I don't have any light on messages on my dash.

Hope this info. helps others in the future.

Thanks for the update. :thumbup:

This is a BAD tip. Google the following and you will know why.

damage from removing battery cable while the engine is running

+1 ... worst idea EVER

Ditto...back in the 60s prior to the introduction of electronic modules controlling many of the car's functions...disconnecting the battery with the engine running was plausible.

But now...with all the CPU controlled electronics in modern vehicles...its not a very good idea. See an exert from one of my BMW's owners manual: