GregMB

Indulge me in a short rant.

This weekend I had quite a bit of time (while sitting on the side of the highway waiting for a tow truck) to think about the thoughtlessness of MB engineers. Over the last couple of days I'd been seeing the "Battery Low - Convenience Features Disabled" warning on my dash..... seemed normal considering the change of seasons here in New England. Cold weather always brings out these sorts of issues and I figured that since my auxiliary battery was a couple years old and was a cheap powersports replacement from the local AutoZone it was simply time to swap it out again. Expecially since after a few minutes of driving the error would clear and everything would be back to normal....

WRONG!

On my drive down to Boston this weekend, I was watching my blinking heat seater LEDs (a surefire indicator that the Convenience Features still haven't come back on) and my lifeless ValentineOne (which runs off a Savvy adapter in the OBD-II port)... it seemed to take an awfully long time for these items to come back on like they usually do.... There was a good reason though.

Turns out, there was a more serious issue than just low-battery voltage on a cold morning.... after about 1 hour on the highway I got this little gem on the display!

(Sorry for the blurry photo, I was trying to capture it while driving and not crashing)


The display says: BATTERY/ALTERNATOR, STOP VEHICLE





Nice.

To further underscore the stupidity of this design.... the COMAND system popped up with the following message as I was attempting to reach the nearest exit to pull off the road:



That's right.... COMAND tells me I only have 3 minutes to start my engine...... AS IT IS TRACKING MY TRIP PROGRESS TO BOSTON AND I AM DRIVING DOWN THE HIGHWAY!!!!


Utter stupidity.... I have a 40-year old Chevy truck that will light up an "ALTERNATOR" light on the dash when there is a charging issue, but Mercedes-Benz in their infinite wisdom has decided that the best way to diagnose an alternator failure is to wait until almost all battery power is completely depleted from both the trunk and auxiliary batteries before displaying any kind of notification......

So.... instead of being able to order a new voltage regulator (I'm willing to bet this is all that failed) and install it at my own convenience, I end up on the side of the road for an hour waiting for a flatbed truck to tow me to the closest dealership where it will probably sit for at least a few days until they have a spot in their schedule to diagnose and repair it.


Anyway.... I guess this serves as a cautionary tale for anyone who sees the "Low Battery - Convenience Features Disabled" warning. Do yourself a favor and go into DYNO mode when the car is running and check your voltage as the car is running.... you should be around 14.4V. If you are, it's probably just a battery that's finally worn out. But if the voltage is anything less.... you've probably got a more important charging issue to identify and fix.


-G

Toadster

at least it's in english


but honestly, that sucks because voltage is a quick check in the dash, but at least you can diagnose easily from here!

AMG55TECH

I have had a similar issue to this... While I was driving, my "convenience functions temperaraly unavailable" popped up. And I though.. "WTF...why would that come on while im driving"?? I can see this being a "normal function" from time to time with extreme weather changes for this to come on right after starting when the battery is really stressed during cranking...but why would this come on while driving. I pulled over as soon as I could, threw it in dyno mode and pulled up the volt meter. key on engine off I had 12.2... a little on the low side, but nothing major... cranking and starting the engine and it dropped to 12.1 and never came up. I was fortunate enough that I was just right down the road from my house when this happened and was able to drive home on the battery. Threw a new alternator in and all was great for about 2-3 months, then out of no where, it happened again, except I wasnt quite so close to home now. I attempted to drive home and while I was making the 5 mile limp home drive, the red "Battery" warning came on the dash... and I finally just pulled over and shut it down and waited for the flat bed. I didnt let the voltage go below 12...didnt wanna fry any components. Got the car towed to the dealer I work at, just to find out that the alternator that I thought was new, wasnt so new...It was a reman... and it was fried. Put another reman alternator in, a new battery and all has been good for the last 2-3 month...KNOCK ON WOOD!!! lol. Hopefully you have better luck than I did. Yes I agree, MB should have a more specific warning for the alternator. I suppose they found it sufficient to have the convenience warning come on... but not every one is going to take that as a alternator issue. So everyone that reads this, make a mental note... "convenience functions unavailable" coming on while driving...CHECK YOUR ALTERNATOR OUTPUT!!! dont get stranded

novae500

Same thing happened to my E500 over the summer. Started up and convenience functions temp disabled, then bam Battery Red Warning. Checked voltage for front/rear. Both were over 12v. Then drove around neighborhood. Steering felt very hard to turn, then Battery/Alternators, stop. Ended up being front battery needed replaced as well as alternator. Picked up a new one from Amazon.

E55Greasemonkey

Greg what was the final outcome?

I feel your pain....and especially embarrassing for an MB tech.My car just did this 150 miles from home. I went to FIXXFEST today, and didn't make it much past the entry gate. Never got to race or see the show. $25 entry and my whole day gone,plus the wasted gas. No real warning, was fine on the highway, except when I was waiting in line I got the COMAND warning about shutting down, then consumer shutoff stage 2 warning, blower to half speed, and I said oh s#$% this isn't good, turned the car off, then not enough battery to crank....Alternator stopped charging! Thanks to MB roadside assistance I had it towed to the nearest dealer today, they had a voltage regulator in stock..they installed it for me while I was waiting,but no luck. Looks like it may be the complete alternator, but they have to order it next week. Towing companies quoted $500-$600 to flatbed it back home, so I left it there to be fixed. BIG thanks to MB of Sarasota for trying to get me back on the road, and providing a loaner car so I could get back home to my family.

berti_00

Awww sh!!it no way bro :/ that suckss

sufyaanahmed

Had a similar issue month back driving down the highway and battery voltage light come on and all my commands go off. Worst part my brakes stop working while I'm driving 60mph. Avoiding other car got in to the emergency lane to a slow stop engine just shut off on me. Changed the alternator problem solved. But very dangerous

StarvingArtist

Wow, it seems the more advanced they get, the more they lose sight of the basics. I hope the airplane guys are doing better!

GregMB

E55GM,

The outcome was an expensive 10 days in the shop for my warranty company.... And a $217 tow bill for MBUSA.

My closest dealer is about 90 minutes from my house...but since I was heading to Boston the car ended up getting towed to MB Shrewsbury.... About a 2-1/2" hour drive from my house.

I give mad props to them though.... They had a loaner car waiting for me (2014 C300) so I could save my weekend trip, and they worked hard to make sure that my warranty company picked up the entire tab for the alternator, a worn upper ballpoint and a major panoramic sunroof repair.

It took more than a week to get everything completed, and more than $3800.... But now the car is perfect again.

I still think that the lack of a simple alternator warning light is inexcusable for a car this expensive (especially considering how dangerous it is to lose battery power on this car!)


-G

turbo97se

It sucks .. while I agree with you that MB should have better diagnosis to say Alternator failed after all they have the technical ability to, when my battery fails on any of my vehicles, I take the car to Autozone, Checker etc to get a free diagnosis to see if it really is the battery or alternator issue. Now what sufyaanahmed experienced, that is dangerous, did you get similar messages beforehand?

Thanks for sharing guys .. will pay attention to this for sure

E55Greasemonkey

Worst part is there is a big red display "Battery/Alternator visit workshop" but there is something wrong with the software that doesn't display this when it's supposed to.

turbo97se

Do you have any recommendations? Any aftermarket devices etc? MB software update? This can potentially be dangerous.

1970gsx

How about just plug one of these things in the lighter socket

E55Greasemonkey

No, this is just the way its designed.I suppose you could run an aftermarket voltage gauge and if you see, say less than 13v with engine running that will give some warning. I wouldnt worry about the brakes...the purpose of the small auxillary battery up front is to keep the brakes working normally in case of a total electrical failure.

novae500

I have a new e55 alternator sitting in my garage. I could send it to u but don't think dealer would like that. Let me know.

efiftyfizzle

Same thing happened to me a week and a half ago... that light just came on and all of a sudden things on the car starting slowly shutting down (convenience features), lights started getting dimmer, etc. Luckily I was a mile away from home.

I figured it was the alternator and not voltage regulator because my car had a burning smell coming from where the alternator was. Changed the entire alternator and now it seems good to go.

I agree though, there should definitely be some type of warning before these things pop up. This is why I don't take this car on road trips or many long drives.... you just never know what can randomly come up.

E55Greasemonkey

I'm going to add alternator replacement as part of my 100k mile service requirements. lol

novae500

$3800. That is steep. Majority of it was the panoramic roof? I got stuck s a $350 labor at Indy for my new alternator I provided the Indy shop.

E55Greasemonkey

Thanks for the generous offer..but they can overnight it for me,and at this point there is no rush. They are also owned by the same corporation as my dealer so I get employee pricing on everything. Thanks for the help!

groove66

That was not a good enough reason for you to check the charging system. seems to be a pretty good indicator if you ask me.
Then you install battery without checking charging system.

Thats why you convenience features were disabled because your battery got low. why do batteries go low. Insufficient charge, bad battery or draw on the system.

isn't the Aux battery just for SBC and engine start and rear battery for convenience features

novae500

I went thru this on the e55 last year. Over a months time I Changed voltage reg, front battery, from relay, battery control module and finally the red battery death code and convenience code finally went away. I replaced each part one at a time until the codes finally went away.

Luckily I gathered the parts and had them available to troubleshoot the problem. So glad for this board to help one another.

cij911

just add a voltage gauge...and while you're at it, add an oil pressure, and oil temperature gauge too....Idiot lights are just that => meant for idiots....

Critter

Gregmb, you state the aux battery was changed out but when was the trunk battery done. Car owners must realize that when you see things coming up on the dash as stated Convenience Features disabled, it does mean something. These cars are power hogs and maintaining a strong battery is a must so replacement at 3-4 years is like insurance paid, you are covered. Waiting until the car fails, all this additional time just puts extreme loading on the charge system which it was never designed for. If you had a ocean going fishing boat would you run to failure knowing you can swim?
My E has the voltage readout when the car starts 12.4 before start and 14.2 running, 2nd battery now,, first one replaced 1.5 years ago, still worked fine but now good for another three years.

moosejaw

You can buy a cigarette lighter voltage meter and the scanguage i have has this readout as well.

EDIT saw the post by someone else

Greg how many miles on your E55?

biggking

So it ended up being a the control module? Where is this at?