castro69

Suddenly when I'm out and driving, the entire dash goes black. The navigation screen, stereo, all lights in the car, the fan unit and the electric power steering system turns off. Even the headlights.
I get several error messages in the screen one second later. And then everything starts up and works. The only thing that can`t be activated is Distronic. I stop the car and start it again, no error messages come up. And I can run for days without anything like this happening. Anyone know what this could be. Have thought it might be the battery in the trunk. But it can also happen immediately after it is fully charged. By going into the "secret menu" I can read 11.6 volts before I start the car. It charges almost constant 14.4 volts when running. Could it be a loose connection in one place?

natcahd

Castro..Don't know the answers, sorry. When you get time I would like to know about the "secret menu"....Thx

Hd

Jason B

Yes, I would also like to know about the secret menu

Mike5215

Right. In the 220 you could get the car to display all kinds of real time engine data on the HVAC screen. It's a back door for the techs. No idea how to get to it on a W221.

The black out does sound like a low voltage problem. The 221 draws a lot of power. 11.6 volts at rest seems low. I'd replace the battery if it keeps happening.

s5benzo

11.6 volts is low my friend. Fully charged and healthy battery should be around 12.5 ish . 14.4 means the alternators cranking out the power..... But if you keep charging a dying battery you will eventually kill your alternator. Change the battery ASAP.

mercedes4ever

11.6V IS THE MINIMUM, ANYTHING LESS REQUIRES A NEW BATTERY.

I keep one of these in the glove box $4.95!! Check Vid...

castro69

Secret menu you get by pressing the phone button and ok button at the same time for about 3 seconds, when the ignition is on the first step. You do not get as much information as W220. But you can read volts, and reset the service.
When I write 11.6 volts, it is with the ignition turned on. And then pulls W221 very much power. Have heard close to 70 amps. I guess it's natural that the voltage drops.
Can you specify what you get with same method.

Mike5215

12.2 at rest.

Jason B

Hopefully that alternator doesn't go bad.

I was surprised to see it's a 220 amp alternator. That's huge!!! Largest stock alternator I've seen in any car. When it goes it's $2,500 from the dealer. See here for better price

S550 alternator

Jason B

I'm good a following directions, but this still isn't working. How about you do a little video or can you go into more detail?

Wonders

castro69 i had same thing happen to my 07 S600 today, displays went blank and steering went heavy but my steering is not electric, has yours got electric power steering is car fixed was it battery.

Jason B

Mike you got into that menu? Would be cool if someone could do a video.

Mike5215

Yeah. Press the start button once with your foot off of the brake, then hold down the "OK" button (left side of steering wheel) and the phone (the button on the right side of the wheel showing the phone being picked up). My favorite thing about the secret menu is the ability to watch all that weird pre-loaded German **** on the COMAND screen. Just kidding...figured I'd torture you some more.

Jason B

Lol. Ok, now I know why I was going nuts! You have to hit the phone button first, then hit ok. I've tried this numerous times, and if you hit "ok" first, then phone, it keeps ask to reset odometer.

Pretty cool. Battery is around 12v when off, when started 14v at 500 idle RPM. If I rev to 1,000 rpm it shows 14.7. I guess the IB's are the amps?

You can even scroll down and see your Vin number. It almost shows the full number, but then has a "..." showing it can't show it all. Haven't figure out how to select it to see the full vin.

castro69

I first changed the large battery in the back. It did not help. It turns out that the large battery charge up the small battery in the engine compartment. And that was broken. So I changed it too. Still I have the same problem that everything goes black for a second.
But the little battery in the engine compartment was very special. It could only be purchased at the Mercedes dealer. And cost 3 times more than an equivalent with the same number of ampere. So I measured it was nice space for a slightly higher battery. So I bought a 62 amp instead of 35 which is originally.

Wonders

what year / model is your car does it have electric steering.

castro69

I do not know if it has electric steering. But some of steering is electric. Because at the moment the car go to "black", the steering wheel is hard a moment. But the engine runs just fine. The car is from 2007

Wonders

yes i have the same problem mine is a 2007 S600, what is yours?

ianerrid

I have a S500 in the UK and mine does the same thing. I have changed both batteries and it doesn't do it as much but it still does it occasionally. The steering going heavy is actually the motor dying for a second or so - I proved this as one day I was idling in a parking lot with the engine running - everything goes off and the it 'reboots'


If you are running the engine restarts but if you are idling you have to manually restart the engine...


I have had the star on it and it just talks about undervoltage, have flashed all the SAMs and it still does it occasionally. Grrrr

Wonders

thanks, i'm also in the UK. have you tried yours with transmission in "S" mode, mine is much improved "S" mode but in "C" mode steering goes heavy daily and sometimes hard transmission shift, think my problem is different in that i have only seen the dash go blank once, has yours got ABC because i think i could be looking at a new abc/steering pump but from what you've said sounds like could be a software problem.

Wonders

ianerrid, "the engine stops for a moment" does the steering stay heavy

ianerrid

No, once it has reset, it all goes back to normal. Mine doesn't have ABC just Airmatic

mb1000

are you sure engine runs fine at that moment ? PS pump is driven by motor and any hick up on engine or, lost power to electrical PS will cause PS to lack of power assistance. Because car is still moving, you can still can handle steering.

To me, could be an ECU related issue. Try some simple things first by taking off the intake / filter combo, checking connection/reseat connection to ecu on top of engine. Check wires, fuses for ecu, etc, reseat/push down all major power fuses. Good luck.

castro69

My Mercedes dealer says I have electric power steering. The engine does not stop when the rest is black. Because it happened while I was standing still in a parking lot at idle. No sign of engine failure. It also happened during hard acceleration. And I notice no lack of power. Diagnosis says only a weak battery. But I have new batteries and car charges constant 14.4 volts.