drey88

I was driving my 06 e55 amg today when i get a message. "Battery low, convenience functions temporarily out" then a little later I get a Red message that says Battery/Alternator Stop Engine. i was close to home so i drove it in garage. When i shut it off a Red message appears again, says " Braking Power reduced then forget the other part. but then i went to open trunk it it doesnt open. no power. I tried to start it again but it dont start. Just a click... what is it most likely, battery or alternator. and why would the brake warning light turn on? thanks for your help in advanced, i know you guys are quick to reply to posts like these and are usually on point

GregMB

Get ready to spend some money.

Sounds like what happened to me. Alternator died..... lack of charge slowly kills main battery (trunk) and then kills small auxillary battery up front (SBC brakes).

Get both batteries on a slow-charge to get them up to full power again, then make an appointment to have the alternator replaced. Don't swap alternators and start your car with dead batteries. Alternators are NOT designed to charge deeply discharged batteries.....


-G

chiromikey

The brake warning came on because of the electronics in the SBC Braking System. Without current, you won't have brakes in a very short period of time after the red message comes on. If you lost all power, it could be a battery but it's more likely your alternator, and further likely just the voltage regulator that's gone bad.

drey88

damn, that is some terrible news!! I mean a voltage regulator doesn't sound that bad. i guess im gonna start with charging the batteries. but then would it be best to check if voltage regulator is bad? anything to prevent having to spend bunch of money unless it infact is the alternator. i mean its only got 80k on it. is it common for alternators to die at that mileage

E55Greasemonkey

Alternator

drey88

im gonna get a voltage regulator tomoro morn and try to change that first to see if it will fix it

qwe4565

about how much to replace alternator?

drey88

i dont even wanna know. ill do it my self if i have to.

Toadster

check the parts thread

cls55tt

Most likely alternator. Happened to me too. The voltage regulator did not fix it.

Try autozone. They were able to get me a replacement for cheap and so far zero issues.

Bigtickets

Happened to me 2 weeks ago. After the car would sit for a few days, after start up, it would give me a battery protect warning. After driving it a little bit everything was good. Then It completely quit working while driving.

All the lights started coming on. Brake warnings, etc. And trust me the brakes
DO stop working.

Bad alternator. 800 at my Indy.

moosejaw

Try this in this order
Check voltage at both batteries at acc and idle
If fine check voltage regulator
If that's fine check BCM Battery Control Module in the back
If that's fine start checking relays/fuses at front and back
If you can test the voltage on your alternator, do so you can eliminate the most expensive problem

I'd rather buy a used w211 OEM alternator than a reman from auto zone. It's a common problem the remans always fail in any Benz. My old c32 went through four in three months with its new owner

chiromikey

Remans always fail in old Chevy's so no way I'd trust them in this car. At least with their lifetime warranty and an old Chevy, you can R/R the alternator in less than an hour every few months when each one fails. Wouldn't want to go through that in the E.

Bigtickets

Agreed about the remaned alternator.


MOOSEJAW: Thanks for the updated signature

austingtir

Mine was the battery... it was 9 years old so looked to be almost the original battery and had dropped a cell or something. The battery voltage was fine but it melted the rectifier pack in the back of the alternator... after testing the battery with my solar BA9 it was clear the plates inside had failed causing the alternator to overload itself or something trying to charge the battery.

So you cant trust a multimeter test. Buy a solar BA9 battery and charging system tester and never have to guess this **** again.

With these solar BA9 you can test the battery and the alternator accurately.

The one in this vid is a ba7 i think not as good as the ba9

novae500

Happened to me last summer on the E500. trouble shooted and ended up being the alternator. Limped to indy shop to get replaced. $434 to replace aux battery and labor on the alternator.

cls55tt

Mine was a reman bosch that came from autozone. I heard they were discontinued for awhile previously.

drey88

so looks like it is alternator. changed the regulator, started up strong, then get messages again on dash. opened the hood and felt the alternator, it got hot really really fast and started to stink as if the copper was burning up...

James M

Get yourself a voltmeter (they are cheap) and check your voltage with the engine at idle to see if the alternator is producing 12V. If your alternator turns out to be the culprit then I would look at refurbishing your existing one as a cheaper option to replacing it. In South Africa a reputable company will whip your old one out, re-wire, replace bearings, etc and have it back in your car within 2 days for the princely sum of around $ 250.00 and it comes with a 2 year guarantee.
I just went through a similar situation and after 5 minutes with a voltmeter I figured out it was the auxiliary battery, but I planned for the worst and made some calls because a new alternator is horribly expensive.
I can also recommend taking your car to a battery replacement center because they can diagnose your problem, free of charge, with their computers and tell you exactly what is causing the problem.

moosejaw

Do not get a reman alternator
they do not work in most of these cars as testified by many here.
A lifetime warranty is no good if you have to keep pulling it out every few months to get that "free" replacement

James M

Thanks for the heads up. Will take your advice if mine ever goes.

angryduc

Have this issue now. Couple months ago left light on in car and battery was dead in the morning. Within days of recharging the battery began to get the Brake warning light.
Checked w dealer and it wasn't SBC Braking system. Now I have these battery warning lights. Thanks for this thread it appears to be my issue.

dyno

really a good dealer if they didn't even check your battery's health with their midtronics tester ..

your battery is quite surely gone.
Low discharge for long time (leaving some light on) = battery killer