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2008 E60 M5 Dinan S2+
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Discussion Starter #1
For the past few weeks, I've occasionally seen the red warning light with battery icon on my gauge cluster stating a charging malfunction - but it goes away after a minute. Always on cold start ups in the morning. If I start up in the middle of the day after I've driven the vehicle around, never see the charging malfunction light. I've checked the battery terminals - battery is a couple years old. The starter was replaced recently by the previous owner by the local BMW dealership. There is a battery tender affixed to the battery terminals, but all the screws are tight.

Yesterday morning, on a cold start-up the charging malfunction light came on - I was expecting it to turn off - proceeded out of the garage and the charging malfunction light did not turn off and then within a few hundred feet of leaving my home. The gauge cluster lit up like a christmas tree and I lost all electrical power. Car was still drive able, as i was shifting - but no power steering, no radio, no hvac, etc. I pulled over into the closest parking lot, turned off the car. Started the car back up and all the electrical power was back, this time a yellow warning light came up stating "check battery terminals". Well, I did that again - saw nothing out of the ordinary in the trunk and under the hood.

Unfortunately, I have not received my system scanner - as it's in the mail somewhere - so I'm not able to read codes. @SunglassesGuy - purchased the foxwell scanner that you have. I then drove off to run errands, and all was back to normal. No warning lights. I was on the road for a while, probably logged about 1.5 hours of driving - doing my usual spirited driving - and no warning lights, all was good.

Starting to guess - is the starter still having issues? Every start up I've done since I've owned the car has been normal. There is no sign of struggle when the engine turns over. It fires up immediately. But the charging malfunction light only comes on after cold-starts. Bad alternator? Can't be, otherwise my battery would be dead. No mice or rodents nesting in my car.

Heading to a local BMW shop to get codes read on Monday. Does this issue sound familiar to anyone?
 

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DinanS2+ e60m5 6MT, s38b38 e28m5 TT/ST3, e30 TT/ST4
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Voltage regulator on the alternator. Very common.
 
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Voltage regulator on the alternator. Very common.
This.....or the alternator. I had similar issues and just replaced both for piece of mind (new alt comes with new VR). And if your battery is near its exp date.....I'd do that all at the same time. You'll be glad you did.
 

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Yup, bad VR left me stranded and had to be towed, luckily I was only 20 miles into my 250 mile trip... :mad:
 

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2008 E60 M5 Dinan S2+
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82 Posts
Discussion Starter #7
voltage regulator is the most likely candidate. Not hard to replace if you are somewhat mechanically inclined. I've done it, let me know if you need help. My car did exactly what you describe.

Voltage Regulator S85
I can't figure out which one is the actual VR part? I am mechanically able but do not have an appropriate location to do the work. I'll order the part and have my local shop do the work. Thanks!
 

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2008 E60 M5 Dinan S2+
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Discussion Starter #9

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going to hate yourself if you go in there and replace the VR and it turns out to be the alternator or the alt goes right after.....just buy an alt and replace both. It's cheap
 

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2008 E60 M5 Dinan S2+
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Discussion Starter #11
going to hate yourself if you go in there and replace the VR and it turns out to be the alternator or the alt goes right after.....just buy an alt and replace both. It's cheap
I was thinking that last night - and you're right. I'm going to drive myself crazy wondering if I should have replaced the alternator - so, I'm getting all of it replaced. :)
 

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I was thinking that last night - and you're right. I'm going to drive myself crazy wondering if I should have replaced the alternator - so, I'm getting all of it replaced. :)
good thinking ;) Get OEM...these cars are extremely sensitive to voltage/fluctuations (as you already know).
 

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Horse is right. But do yourself a favor already and buy a digital multimeter. Measure the voltage at the jump terminals with the car off. It should be no more than 12.8v. Then, start the car and measure the same point. If it’s over 15v then you have a bad VR. If it’s 13-14.5V then you don’t have a VR issue. I’d get a decent used one off of Craigslist list. Search for Fluke. You can find these for like 50-80 which is like 10% of what they were new. I‘d avoid the 20 POS at harbor freight.
 

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I mean, not that I disagree with replacing a worn component in full but for $40 it was worth it to me. Car still rockin and rollin on the original alternator at 200k
 

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2008 E60 M5 Dinan S2+
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Discussion Starter #17
To me the part that is telltale to Kimchee's story is that his issue is intermittent/temperature related.
Yup. Been driving it every day to see if I can reproduce the issue, and the car has been trouble free for the past 4 days. I just received my autel multimeter/OBD code reader. Charging as I type this. Will run some alternator/charging/battery tests to see voltage. That should help narrow this down. My local BMW shop is surprised with the number of VR failures on the forum. Nonetheless, more investigating to come.
 

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2008 E60 M5 Dinan S2+
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Discussion Starter #19
Yup. Very good point. Gotta love that it's most likely a $35 part. Unfortunately, I don't have an appropriate location to do the work myself - otherwise I would. My local BMW shop is going to take the car apart anyways - so if I'm going to pay 3rd party labor costs - I might as well have "peace of mind" and replace the alternator while I'm at it. In addition, I'm having a bunch of additional work being done, so it's a good time for me to consolidate as many "repairs" as possible.
 

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Yup. Very good point. Gotta love that it's most likely a $35 part. Unfortunately, I don't have an appropriate location to do the work myself - otherwise I would. My local BMW shop is going to take the car apart anyways - so if I'm going to pay 3rd party labor costs - I might as well have "peace of mind" and replace the alternator while I'm at it. In addition, I'm having a bunch of additional work being done, so it's a good time for me to consolidate as many "repairs" as possible.
I just noticed that you're in Issaquah WA. I'm not too far from you on the Canuck side, used to drive through your area on my way to eastern BC (going through Spokane etc. avoids some pretty hairy mountain passes on the Canadian side).

Hopefully soon our countries settle down and we can get back to the spirit of freedom. I really don't like the way things are now.

What you say about consolidating a few items makes sense. If at all possible I would look into getting some ramps or something like that at least so that you can check things out on your own here and there - I know you've said you don't have a spot to do much, but a few of these kinds of things have saved me thousands over the years.
 
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