Hello Mercedes enthusiasts,

I'm reaching out with an issue I've encountered with my 2011 Mercedes S550 and would greatly appreciate your insights.

Recently, upon starting the car, an orange battery icon appears on the dash within the first 2 minutes. Subsequently, the engine stalls, and in some instances, everything goes blank before the entire electrical system restarts. Interestingly, the analog center clock also resets itself by going back 12 hours, akin to a battery replacement.

I'm aware that the orange battery indicator typically signals a charging system problem. However, my battery is only 6 months old, and the alternator has passed the shop's diagnostic check.

I'm perplexed by this recurring issue and would love to tap into the collective wisdom here. Any ideas on what might be causing this anomaly and, more importantly, how to address it? Your assistance is immensely valued.

Thank you in advance for your expertise!

 

there are hundreds of posts with this error - and not a single owner has ever come back to explain what cured it - its a standard feature of the >2009 w221 facelift cars

many swap all the batteries (the small under dash one, and the main front battery), then they do the expensive battery control module, then they give up and it seems move the car on - I suspect its a software feature - that 'wrongly' becomes active once its not been plugged in a main dealership for quite some time - hence a line of 'accidental code' turns on a magic warning light - this 'unfortunate extra' managing to illuminate warnings on the dash display by accident, has, post the VAG dieselgate scandal been found to be affecting quite a number of much later mercedes models....

 

Thanks for your response. Do you think this fixes the issue?


I just added a video to my thread that you may wanna check out.

Thanks!

 

general note : its is possible you have more than one issue - its a Mercedes (so expect lots of issues all the time - some of the least reliable cars ever made since a paradigm shift circa 1998 by their accountants).

just saw the video - that indeed is far more serious than the common bug I point out above in post 2

I would NOT try to drive the car with that bug - somewhere must be a serious electrical connection problem. Either the action of the ISM (the bit putting it in gear when you move the column selector) or the engine / gearbox movement is breaking a circuit...

There is so much electrical stuff on the w221 you need to go slow, disconnect batteries and start checking tightening any obvious electrical connection. These days cars use so much current, they have bolted on main electrical connectors (check under the bonnet, some in the footwell, some around the battery under the bonnet, and I'd check engine earths, and the alternator and starter connections (don't fiddle with these with batteries connected). If that is inconclusive - look for wiring damage, from mice, chaffing, bad placement or multiplugs where the plastic housing has broken up, and inside the Front SAM a black box with screw on lid near the brake reservoir for anything lose, wet or corroded, (and if required the Rear SAM and other connections in the boot).

and NEVER wear rings or watches when doing DIY or working on cars - a short circuit making a wrist strap or a wedding ring glow red hot can mean you easily lose a finger - let alone de gloving a finger (pulling the skin off) catching a ring slipping off a nut or touching something hot - or slipping down a ladder etc.

re your second post

you say you have a 2011 car (likely with a different engine to the 2007 one you have in your point of post 3 above), those early versions of the M273 engine came with a defect (chocolate components - the ones driving the camshafts) and this causes most of the cam timing issues, later it was found the sensors were cheap and nasty and some didn't function correctly, let alone the fact these same sensors leak oil, that by a design feature manages it to escape down a wiring loom and blow up the engine ECU.

there can be thousands of reasons its running badly - a common cheap repair all Mercedes cars need every 50k or so miles is a new crank position sensor. About $50 and doable at home - Aside from that general maintenance trick - you need to plug in to high end diagnostics tool and review the likely 5 to 10+ error codes - if its mostly 10 years of built up gibberish, delete them all - then go for a 10 min drive anything that matters should pop straight back

.

 

Thank you so much for your help and writing all that. I had it towed to my mechanic and handed him your notes. I will post here when I get updates from him

 

not a bad idea - they are terribly complicated and without experience of where stuff is and what usually plays up - alongside decent diagnostic gear - it could be a painful and fruitless home job

please report back - its always good to close a post down with a good conclusion - it helps others

 

Update: They tested the alternator and apparently a module was malfunctioning and they replaced the alternator. It worked with no problems for one week until last night. The heat was on and I sensed a burning smell coming through the vents. And then the battery error popped up on the dash again. Stopped the car and monitored battery data and recorded this video. At first I thought there was another problem that was not fixed but, now I am assuming it was the new alternator (it is a reman) that got burned however I am not sure. Any thoughts?


I am getting it towed to the shop again tomorrow and will post an update.

 

that's not correct - burning smell sounds bad.... open the bonnet and double check the drive belt is still there

usually as soon as it starts it should behave like this bit of the video

 

sepehrkz
I am having the same issue with my S550. Did you ever find the culprit ? Both batteries are charged. However, the starting battery tests 12.3v when connected and 12.6v when positive is disconnected.

The battery light was on when I parked it. Shut the car off and everything went dark. Nothing would come on. I connected a battery charger to the battery without it plugged in, it sparked at the negative and everything came back on. It is worth mentioning the voltage of the main battery was under 3v when it was dark. When it came back on (and before I charged it), it read 12.3v. Go figure. My mechanic loaded the alternator and found no issues. Any help here would be appreciated.
-Mike

 

Hey! First time I got the orange battery indicator on the dash I first took it to a mechanic shop, they tested the battery and the alternator and both passed the test. Then took it to a better shop with more experience with European cars. They said a module in the alternator is faulty and needs replacement. It worked fine after the replacement. Then I got the orange battery on the dash again. Turned out the serpentine belt was broken because one of the pulleys got stuck. Replaced them all and it has been working fine ever since.
Hope it can help you fix your issue!