A_Nearby_Tree

Hey guys,

I've had my 05 E55 for about a month now. Everything has been great except the gas mileage.

Last night I turned the car off and was walking in my door when i heard a weird hiss. Honestly thought nothing of it.

Went to start my car about 30 minutes ago and it gave me a "Reduced Brake Power" message. Started googling and it looks like it could be a few things. I just went back out to the car and tried starting it, i have a low battery message that then turns into the brake power message.

From reading it looks like it could be as easy as replacing a battery or as bad as replacing the major brake parts.

My question is where would you start or is there a way i can narrow down what to fix?

Thanks for your help.

A_Nearby_Tree

So the more I mess with it I believe it is the battery but am not sure which (there is atleast 2?) or where it is at.

Is this battery only sold at MB dealerships?

Thanks

novae500

two batteries, one in the trunk and one under the hood, passenger side under black plastic box. You can pick up both batteries at your local autozone, etc...

A_Nearby_Tree

Thanks, the one under the trunk is fairly new. I haven't looked at the one under the hood yet. I'll be buying a MB battery.

Would the one under the hood cause these problems?

2000UZJ

The one under the hood is the brake battery. If low it will create issues.

dchl21

trust me ..the gas isn't bad for what it is .. there are things way worst..


SBC replaced before ?? maybe bring it in to get it figured out... happened to me ...loosing brakes while driving is no fun.

shardul

iTrader: (1)

they sell for about 100 to 150

A_Nearby_Tree

So bought one for 150. Now the car wont start says ESP and another Malfunction.

Just got back into car and now everything is dead.

Any ideas?

Edit: I believe it may be the alternator? Does this sound right?

A_Nearby_Tree

I dont believe the sbc has been replaced.

2000UZJ

Everything tight? Check voltage at both batteries and unplug both for a few minutes.

A_Nearby_Tree

Everything is tight, voltage is good.

E55Freak

have you tried jumping it? alternator won't take over until the car is started so it has to be battery related...short, not enough juice to start...replace main battery??

A_Nearby_Tree

I havent jumped it, voltage is good. The main battery was recently replaced.

Could the voltage regulator make the car completely dead?

Edit: it won't let me turn the key and no lights are on.

edgar86

It just happened to the wife of my friend , car stalled on the road , everything dead , brake was barely working , because of no assist ...
Car was towed back .


should be the voltage regulator + fuse check up .

cmriv

all these speculations and no one pointing in the direction of actually diagnosing.

What are the post dates on both your main systems battery and aux battery?

if you can get the vehicle started again, jump start, get a volt meter and put 1 lead on the positive and 1 on the negative terminals of the battery, that right there will determine if your alternator is failing.

A_Nearby_Tree

Main is feb of 15 the aux was 23 09 but the new one is 43 15.

cmriv

if both of your batteries are new, and you don't have a tester readily available for the batteries, see if you can get your hands on a meter.

If not then you should hit autozone or advanced up and have them do the tests.

Maybe your BCM, battery control module took a poop. Charging voltage should be your next step though, if the vehicle will start....

A_Nearby_Tree

Yea car is completely dead but both batteries have a good charge.

Picking up voltage regulator now to see if that works.

cmriv

Wait, do you accessories and light and all that junk turn on????

A_Nearby_Tree

Nope nothing. Cant unlock doors or even get car in neutral.

JoeJErnst

Do these cars have a fusible link or other type of master circuit protection? Your description makes it sound like a fuse or circuit breaker is tripped preventing any juice from flowing to the electronics.

cmriv

So your key wont turn in the ignition at all???

gjunon

Is the car even turning over?

A_Nearby_Tree

So the main battery is now dead. I have to jump it now.

After hooking it up all power works. The first time it cranked once, everytime after that no cranking.

Now it just says visit workshop with a battery symbol.

Thanks for all the help guys.

Im done for tonight as it is pouring. Tomorrow after work i am switching out the voltage regulator. If thsg doesnt work it is getting towed to MB.

Ls1toAMG

I would pull both negative cables of the battery's.