Gangplank

Can it fail intermittently? Drives fine for 3 days then faults, clear codes & drives fine for a few more days.

sanjsanj

yep, that's exactly how my alternator went - for some fucking reason the battery sign doesn't come up if the alternator isn't charging. I needlessly replaced the battery thinking all was okay then 3 months later same thing 10 mins after start - luckily I had the secret OBC menu unlocked showing me the voltage and I saw it was sitting at 12 and slowly dropping towards 11 instead of being at 14. 5 mins later the alternator would come back to life. That's when I realised the alternator was at fault, replaced it and had no problems since.

Drive around with voltage showing in the OBC at all times from now on so you can monitor its state.

should be 12.3-12.6 with key in pos I
12ish with key pos II
and shouldn't go much below 10 volts during start up if it's a good battery/not too old.

AbyssalCreation

It happened again today when i was with a friend. I noticed a few blinks from the idrive and bolted my way home. It drove fine for the 20 mile trip back to my place. I let the car idle in the garage for about 15 minutes with the AC and music playing and just waited for it to happen again.


The battery is extremely weak now and struggles to start. I had the battery recharged about a week ago.

- Alternator is new and has been replaced twice
- Battery is new
- 4 prong relay part #61366901469 is new

Now, the IBS sensor is still in place and is not unplugged. Should i unplug the sensor and check the OBC menu? sanjsanj, help me out here man.

Gangplank

Strange problems.

sanjsanj

and should be between 14-15 with the engine on.

It's a shame you didn't catch this with the voltage showing on the dashboard - would have been a good indicator of what's happening.

If it is in an overcharging, all the modules switch of to protect themselves, which would cause the error lights to come on. You may have changed the alternator but you need to monitor the voltage to see if it's actually working or not

Gangplank

That's some good advice to have the voltage showing. Here is a link to the how to PDF from scoopz @ M5 board. http://www.scoopz.com/m5board/E60_Hi...structions.pdf

The other solution is to get one of these cigarette lighter socket voltage monitors:http://www.amazon.com/s/ref=sr_st_re...rt=review-rank

They made some that include a USB port:

5_series_T

Im having simular problems and I have to change the positive battery cable. The wires started to burn. Hopefully that solves my problems. Battery would not hold charge. Hows your situation going?

H F

Make sure the terminal bolts are tight ,, if not it can start to burn the cable and trip the disconnect feature,,
and threw the tranny in safe mode also ... That happened to me about 7 years ago when I first got my car.

strobeyprobey

Wife just had the iDrive and HUD turn off while driving on the freeway, two days before it wouldn't start reporting low battery in her 05 645.

Using the BMW DIS I found a bunch of over-voltage warnings. When I was watching the voltage and rev-ed up the engine the voltage shot to over 17V! So that's when many modules power-cycled. Also the DME reported there was no communication with the alternator.

Since I didn't have time to look at the alternator myself, the repair shop just reported the alternator wasn't charging at all for them. So they are replacing the alternator. I just ordered a relay as reported earlier on eBay for $17 for good measure.

JAYS545

Get the battery registered if that hasn't already been suggested.