any techs on here please help, many problems, transfail safe again

[IMOLAredNC4.8is]

My 2004 X5 4.8is has been in the shop now for almost 4 weeks. The car is [COLOR=blue ! important][COLOR=blue ! important]reading[/COLOR][/COLOR] DSC 4x4 Inactive, Self Level Suspension Inactive, Tire pressure light, ABS light, lose of [COLOR=blue ! important][COLOR=blue ! important]power [COLOR=blue ! important]steering[/COLOR][/COLOR][/COLOR] and the radio will cut in and out and the nav screen will flicker on and off like crazy. If I am driving down the freeway I have no problems at all. As soon as I get off into stop and go traffic thats when the car starts going crazy. All those warnings and faults will start popping up almost everytime the car is just sitting at an intersection or stop. I will pull away and the car will barley drive. Sometimes i get transfail safe prog message too. I took the X to hendrick BMW they could not get the car to reproduce any error messages so they replaced the EHC module thinking it would maybe solve the issue. 1000$ later the car is doing it all over again. I thought back to right when the car started doing this. It all happend after i had my [COLOR=blue ! important][COLOR=blue ! important]amplifier[/COLOR][/COLOR] turned all the way up on my after market system. We went and had the alternator and batter tested today, both came out fine. But we were told the [COLOR=blue ! important][COLOR=blue ! important]battery[/COLOR][/COLOR] had a very low charge to it. We disconnected the amp and subs about 4 weeks ago. I was told that the battery had been drained down to a very low charge from the after market amp and the alternator would not charge it back up to its full charge it would just maintain the low voltage reading. So my question is if we charge the battery back up completely will it run fine if the car is working off of a fully charge battery? The little eye in the battery was completely black. Other question is that if the battery voltage dropped to that low point will it go right back to that low point again and not hold a full charge? And is it possible that if the car is running on such low battery power it will cause all these faults to come up? Please help and thanks for your time. (oh and the only time these faults come up is when the car is driven around town in stop and go traffic) also i was doing some research and ill add that i did replace my brake pads myself and now i still have the red brake light on my dash. Someone said the sensors might need to be replaced

[IMOLAredNC4.8is]

Also add that the alarm system will randomly go off when the car is just sitting.

[roadfrog]

First thing that comes to mind is alternator, especially since it happens at lower speeds/rpm.

[Weasel]

The alarm going off is likely an unrelated problem, I'd just have the alarm counter read out when at the shop, it will tell you what set it off and how many times.

From the sound of it you may be having alternator problems, specifically problems with the diode trio when it gets hot. At a more constant rpm it will act ok, like on the highway. But when at low rpms as well as when the rpms go up and down the diodes can let too much ac voltage through, as well as the battery back feeding the alternator.

I'd drive it until it is doing it and then while it is doing it pull in somewhere to test the alternator... and make sure they test the diodes with it.

Hopefully that is it. Otherwise get the diagnostic report faxed to you from the dealer (from the first time they hooked it up, before faults were cleared) and you can scan the pages and upload them and send them to me, I can look at them and give my take.

[IMOLAredNC4.8is]

That is going to be the next step, get the codes to come up and see what the alternator is reading. The alternator has been tested probably about five times now. Everyone is saying it and the battery are testing fine, but this has not been done when the problems are occurring. Is it possible that the battery has permanently dropped its charge and low voltage is causing all these faults to appear while driving in say stop and go traffic?

[Weasel]

I wouldn't think so, but an easy way to desulphate adn kinda rejuvinate a battery that is getting weak is to put it on a high rate of charge like 30-40 amps overnight. That will bring the battery back, and will do much better for the battery than any trickle charger can ever do.

But definately have the alternator tested while it is currently acting up, and if it has been at the dealer they will have the full diagnosis report in the vehicle's file that can be copied/faxed to you. The diagnosis report not only shows every fault stored in the whole vehicle, but what paths they took in the diagnosis process in the machine. Would be a good thing to have.

[IMOLAredNC4.8is]

That was one of the major problems while it was at the dealer. I had taken the car to a local bimmer/merc shop and they said they problems were beyond their abilities. While there they cleared all the codes in the car. So when the car was hauled to BMW they had no history of any problems in the car. Because of them not finding anything they went by what I told them was happening and they put a new EHC module in the car. This did not fix the problem at all.

[Weasel]

But now that it had happened a few times since then there will be faults stored now. If the alternator doesn't test bad when the problems are occuring, bring it back in to the dealer for a proper diagnosis.

Does the other shop keep printouts at all? (not likely)

[X5NTahoe4u]

i had the same issues and the battery was not charged fully. the current is getting low causing the "computer on wheels" to freak out due to low power. The alternator is charging the battery when your driving and draining the battery in stop and go traffic due to low rpms @ idle. Just a guess. I had similar issues and they were electrical related.

[IMOLAredNC4.8is]

X5NTahoe4u- What did you do to fix the problem you were having? Sounds identical to mine.