Kawa86

Hi all,

Last year I bought a 520d from november 2007 (lci) with 200k kms.
Since then I been having a problem.
Sometimes when I start my car, the Idrive screen is black.
But the I drive still works, I can change the channel on the radio and if the navigation was in use, it still continues.

On my dashboard the engine fault light sometimes comes on, and then goes away again.
Also about every few minutes I get an audio warning and the ABS and engine light comes up, and I get the (red) message that I need to go to the garage.
And my speed and rpm dial seem to reset themselves every 30 sec or so. (they drop to zero and come back up.

This situation last for a certain time and than it goes away, and everything goes back to normal.
It even stops when I'm driving long enough, but mostly after I restart the car after a stop.
(it never starts when I'm driving only if I start the car)

This whole situation does not seem to affect any other function of the car, but the cruise control does not work and the blinkers seem to sometimes have a delay of half a second.

In the summer it only did this for like every 3 weeks, but now (colder) it starting to happen
2-3 times a week.

I asked a local BMW expert but he has never seen it before, so he wants to look at it but does not know where to start. (so I want to avoid this because it will cost allot of money...)

I already repaired and checked all the wiring in the rear hinges. (it was a mess so it could have damaged something but for now the wiring is oke)

No water in the spare wheel, and the box in the spoiler also seems dry.

So if anyone has seen this problem or has any suggestions I'm happy to hear them.

Thanks in advance!

TwoPedal

I am by no means an expert, but I will lend my thoughts.

First of all, have you tried the reset method for iDrive? Simultaneously press both eject buttons (CD & NAV DVD) and the volume knob for a few seconds. It will reboot the system.

As for the other problems, do you have the large sunroof? They have a tendency to leak and when they do, water often drips onto the fuse panel and battery (passenger side of the trunk) and then under the spare tire where many electronic components are located. If you take the cover off the rear passenger side of the trunk, you can look at the lining, tray, and other areas to see if it looks like water came in.

Another theory is your battery. Is it original? These cars are very sensitive to voltage fluctuations. If your battery is weak and not providing the appropriate voltage, strange problems will happen in different areas of the car. Has your iDrive time & date ever reset? Has your dealer plugged into the car to check for stored codes?

paulie

Based on your description, it seems like a battery problem. Perhaps it is deteriorated and needs replacement. If you do so, make sure that you don't forget to "code" the new battery in. That would be my first focus. When the battery is low, many systems will be shut down or run in battery-safe mode. Perhaps the IBS system? It is weird that the BMW expert stated he doesn't know where to start. First I would simply read out possible errors and check if they indicate any electrical error codes.

I wonder why you replace cabling in the rear? Where there problems with it?

Kawa86

@Twopedal
When I took my car to the BMWexpert, I watched him do the reset procedure but nothing changed.
I don't have a sunroof, and I checked the spare tire area, but everything is dry.
I have not checked if my battery is original.

@Paulie
I'm also inclined to look into the battery/alternator direction.
When I get into the car and insert the key, everything works like normal (screen is on).
It is the moment that I start the engine that the screen goes black and the problems start. (voltage drop?)
Is there any way to check the IBS?
The car starts good, so I don't get the feeling it drains overnight or something.
The BMW guy said there would be nothing to read in the computer,
personally I get the feeling he only wants me to bring in the car, and secretly already knows the problem.
I was there with the car, when the car had the problem and he didn't wanted to hook it up to the computer...
Is it possible to code the battery from the car, or do you need the computer?

The cabling in the rear hinges, had the typical problem at the point they need to bend every time you open the rear door.
They where repaired before but in a not so ideal way.
I had taillights falling out and the rear glass open button didn't work anymore.

Thanks 2 both already for the reply's!

DaManNi

Hi.


Did you ever get this resolved? I have a similar problem in my 530 SE but usually only after heavy rain or a car wash. I've checked the battery and fuse area and they are all dry.


Any help would be appreciated.

paulie

>> Is there any way to check the IBS?
By reading out the error memory.

>> Is it possible to code the battery from the car, or do you need the computer?
You need coding tools to do this.

Btw. Try perhaps a new battery. Sometimes it is something simple.

Lotus99

I hear with the BMWhat app and a smartphone you can register a new battery. Look into it if you don't want to go the full coding route.

Anzafin

My vote goes to voltage regulator. I've seen this happening several times.
Monitor your battery voltage through the secret menu. If it varies a lot during driving, and especially if it goes higher than 15V and the glitches happen at the same time, it is probably the voltage regulator inside the alternator.

- Antti -

Kawa86

Thanks all for the replies, yesterday I measured the voltage of the battery before I started.
It was only 12.0V, when I inserted my key it dropped to 11.8V.
So I went to my local bosh store.
Bought a shinny silver bosh battery (150€) and since I installed it I did not have the problem anymore.

So far so good... but

When we tested my old battery with 2 different battery testers the result was not 100% but it was not to bad either. There where no dead cells or something, but the charge was just 61%.
The Boshguy which I trust, was not to shure the battery was the problem and told me to test it a few days before I would turn in my old battery.

2nd thing is the charging voltage.
Yesterday when I started the car the voltage was 15.5v which of course is pretty high.
But Boshman told me that it could be normal since some modern cars do this to coop with the initial high current demand of the cold engine, computers starting, seat heating and other stuf.
But it should drop after a short while to the normal values.
And shure enough it did drop to 14.7V after a short while.

However this is still a high value, and according to the Boshguy it is not very good for the battery.
Today before I started the car to go to work I activated the hidden menu to monitor the voltage.
The voltage was 14.6v-14.7v from the start and it stays very stable at every engine regime.
After about 40 min it dropped very slightly to about 14.5v-14.6v.

So if anyone knows what the normal charging voltage should be on this car?
It has 220d km's and a Valeo alternator.

Thanks in advance!

paulie

Great that you solved the problem. Related to the "high" voltage on your battery. That is the reason why you MUST code the new battery to the car. All the charging electronics need to know that there is a new battery and its amps characteristics in order to correctly charge and adjust settings. I would drive by a BMW dealer and ask for it to be coded. It is not more than 15 min of work.