tp320

Hi,

I've browsed through the forum and found other people having the same kind of problems that I'm now experiencing, but haven't found any solution to them that I wouldn't have tried yet.

So here's the thing... The car is a 2003 520i, around 120.000km on the odometer. Has been mine since it was new. There have been some electrical gremlins and other problems along the way (the seat heater once put the seat up in actual flames and burned my jacket - thankfully the car was under warranty and BMW replaced the seat AND the jacket...) but nothing that the dealer hasn't been able to fix - until now.

I don't know if this is relevant but I should note that last Summer during a car wash the car suddenly gave all sorts of warning messages, the windscreen wipers were on all the time etc. etc. I managed to drive it to the dealer and they hooked it up but the computer didn't even recognize the car. After some review they came to the conclusion that the control box was faulty. It was replaced and things started working again. They didn't find any moisture anywhere so I guess it was just a coincidence that this happened during a car wash.

The car worked fine for a while but has now been plagued by error messages and problems for some time. Based on some of the threads I read, I guess you have read about these before, but here goes: The car always starts without problems and sometimes a trip goes by with no problems. But during about 20% of the trips, I start getting the error messages (they might appear after 5km of driving, or 20km, or 50km - no pattern there). First the iDrive flickers for a few times and then there's either a message that the battery terminals would be loose or that the battery charge would be low. It can be either one, but it's always one or the other. And immediately after that there are the error messages for ABS, ESC and "transmission failure".

If I stop the engine and go for a coffee, the error messages are gone when I get back and the car works again - at least until they re-appear (perhaps not during that same trip, but eventually).

Here are the things that have already been done to check where the problem could be... The alternator and the battery have been checked. They both work (I don't know how a battery is tested, actually, but I've been TOLD that it works, so... and it's only 1,5 years old). The dealer's computers do show the error messages, of course, but no solution to them. According to the computers, the battery's charge has always been good. The car has also been driven regularly and while it's rather cold out there at the moment, it wasn't when these problems started. Also, one would think that after 50km of driving, the car would've heated up, so I doubt it's the weather that's causing this - especially since the car has been through several harsh winters without problems.

They did the usual things. Double-checked the battery terminals and, as mentioned, the alternator (which worked fine - 14.5V, if I remember correctly). They also apparently re-programmed the control box to make sure that it recognizes the battery. These didn't help.

The last time they thought they might have found the problem. They changed one relay and the sensor responsible for checking the battery's status. I believe this was the IBS sensor? So it was changed and programmed. But - no help.

So now the car is going back to the dealer. I don't expect miracles from them but even though I can drive without ABS or ESC (I've certainly been through quite a few RWD-cars without those), there are the other things that pretty much make driving a pain (mainly the transmission going into some kind of safety mode).

So if the control box is working, the alternator is working, the battery is working and the IBS is working (at least it should, since it's new), does anyone have any ideas what the next step should/could be?

nicke60gre

I've had the exact same problems. All of them you mentioned for about 7 months!! Maybe twice a month or maybe sometimes twice a day ...if weather was wet. When I was turning the switch off and on again, everything had been cleared.

Every now and then I had I-drive messages about battery terminals, ABS malfunction, also A/C fan speed was unstable, wipers sometimes were working on their own (2 times in 7 months long)

Check if your battery (Battery Ah - plain battery/AGM battery) has been registered with SSS.
Sometimes MPM fails and needs replacement (Micro Power Module)
Veleo alternators are crap. I replaced mine (Valeo) with Bosch and have never seen a single fault pop-up since then...

Battery registration and alternator replacement was done at the same time along with CIP update, so I can't specify the exact reason that caused the malfunction.

I hope that helps.

craigm1841

I am sorry, I have no valuable input, I just cant believe your car lit you on fire. You should nickname her "Christine"

you shouldnt have gotten the "fireplace" option when purchasing your car.

tp320

Many thanks for the suggestions. These are especially difficult problems because you can't replicate them at will. They appear without any pattern. The service guys can see the codes and know that there's a problem, but since they don't know what causes it, they don't know if what they've done has fixed it or not. Only time will tell.

BMW also seems to have a mind of it's own in the situation when it thinks the battery's charge is low (even if it, in reality, isn't). It apparently SHOULD start shutting down all the "non-essentials" in a certain sequence to conserve energy. And sometimes it indeed works and you can see that the radio, Bluetooth, A/C and things like that stop working. Then on other times it turns ABS/ESC off and transmission goes into the "drive moderately-mode" while the CD-player and other minor things continue working fine.

Anyway, a bit of trial-and-error should sort things out. Thankfully the local service now does these fixes free of charge since they offer something of a warranty to their work.


The seat heaters... They are standard equipment here in Scandinavia (hopefully not this "fireplace"-model, though...) and the first cars delivered had faulty units that could indeed cause a fire. It was a rather cold winter day and I had a heavy winter coat on so it was the smell that alerted me to the fire. I stopped the car, noticed the smoke and a few flames which I put out with snow. Nothing that serious since the fabric doesn't really catch fire but the coat was indeed ruined and there was hole in the in the lower back area, of around 15cm in diameter. Ironically, I received a notice of a product recall concerning the seat heaters less than a month after this incident....

I have to say, though, that when they're NOT trying to burn the driver, I consider BMWs seat heaters to be the best I've experienced. They're not the most powerful but they're up there and what's really cool is that you can use iDrive to set how the heat is distributed between the seat and the back. Usually I have a heavy winter coat but light trousers so the back is not even warm when the seat is already a bit too hot. With this, I just distribute more heat to the back - works like a charm. I guess other cars might offer the same thing now (haven't seen any, though), but this was the first for me. A great feature.

tp320

Just a note that if my problems were the same as yours, it appears that the solution was also. They let the car run on idle for a long time and everything worked until the alternator suddenly ceased working. And it started working again after the engine was switched off and then on again after which it again failed after some time. Sometimes it took five minutes, sometimes five hours. Apparently the car doesn't recognize that the alternator is no longer working (which does sound weird, but is apparently true - the shop's computers only give a real-time figure) but does, of course, recognize the drainage in the battery, hence the problems and warnings.

Anyway, after all the software had been updated and the alternator replaced, the car appears to be working perfectly now. I don't know which company supplies the alternators used here. There was no mention of a manufacturer, only BMW's own markings. They appear to be pretty reliable, though, since they had only replaced about a dozen of them.

This seems to be a rather common problem and especially difficult since the car can be kept running for a rather long time (say, two hours) without the problem appearing, so the service guys are in trouble trying to find what's wrong. Thankfully they now had the patience to test it thoroughly and finally managed to see the problem themselves.