low voltage - whats going on?

[jberks]

Hi all,
mentioned this before. 2003 E220cdi (211). Wouldn't start one morning so we replaced the battery. Later found out that the battery we replaced was only 2 years old and probably fine.
Since then, every few days we get a consumers off message. Left longer, it does start turning things off. Parktronic didn't work this morning though the radio was fine (odd?).
I suspect, left long enough and she wouldn't start. After a run she's fine. after a charge up she's fine.
We've had an auto electrician spend over an hour on it and he can't find a problem. Current draw is nominal, charging rate is fine.
Is there anything that can suddenly wake up after being parked for a while?
Any ideas gratefully accepted....

 

[television]

Not unlike mine if left for a few days, consumers off for 10 mins.

There is not that much left over to charge the battery when you have the lights, heating, demisters, sound, and I think that we just have to accept the situation
The car draws less current locked than un locked

 

[Donk]

Jberks, you may want to visit your dealer and get the battery modulator software updated, and the only reason I say this is thats what been done today on my 04 W211.

On and off during the summer I would get the consumers off message that dissapeared after a few minutes of running, and my dealer could never find anything wrong. Yesterday, despite being driven the day before with no issues, the car would not turn over, just a solenoid click, the clock was spinning anti clockwise, brake warnings were flashing up and all sorts of other warning lamps were flashing and buzzers beeping. The Mobil callout guy jump started the car and said he could find nothing wrong i.e. no error messages etc. Took it to dealer who could also find nothing wrong but say they get loads of consumer off issues like this when the weather gets colder. They updated the software, so fingers crossed its sorted although I'm not full of confidence about this. It prioritises what needs to be on i.e. lights are high priority and heated seats are low etc when the weather starts to turn cold as you probably know. I wonder if the new software has changed the voltage limit tolerances or something, but its interesting to note that they also said this 'feature' has been deleted in the 2006MY onwards W211's.

HTH.

 

[jberks]

Thanks guys. I suspect it is a software issue as the battery is new and the car is currently getting more running than mine, doesn't have heated seats that I am using all the time at the moment, yet mine is happy and his is complaining. It is used every day so I doubt the voltage is really that low, though the battery we took out was genuinely flat which is confusing.
If the controller went haywire, could it stop it charging?
We have been advised by the indie to change the way we are charging it. Previously, as we were scared of blowing anything, we've been charging the battery with the earth lead disconnected. The tech tells us that we'd be better leaving it connected but putting the earth lead of the charger to the earth on the module that the battery connects to, rather than the battery. Something about this module knowing that we're charging. Apparently, another possible cause they've found on some cars is corrosion at the second battery (SBC backup).
So, its been on charge as advised last night and if it's still misbehaving in a few days, she's going to the indie for a more thorough checkup.

 

[Mr Teddy Bear]

I was alway's taught to remove a battery before charging with an alternator in circuit to protect the rectifer diodes? However perhaps ttechnology has moved on ?
My 230KSport has a 88APH Excide Battery fitted that's alot bigger than any website I've looked at recommends........................
If your battery is in the boot there is a comparatively large constant volt's drop. Ideally the starter battery should be within a foot of the startermotor.
With a low tech car the radio wont work while the engine is cranking.

 

[type49]

Good advice about the update. There was a recall to the battery control module which was a software upgrade, so should be freeeeeeeeeeeee

 

[Ellsy Tanners]

The above posts are correct, a software programing for the battery control unit will stop the warning message from coming up.
However the system will still work the same shuting down consumers, but you wont be told about and therefore wont worry.

Wot you dont know cant hurt you!!

 

[television]

Wot you dont know cant hurt you!!

I wish the 230 was like that

 

[jberks]

Update.

Charge up didn't do it so the indie have had it in today.
They tried to apply the update to the battery control module, couldn't and subsequently found it to be on the blink (not sure how you identify a duff module aside from the fact that they couldn't talk to it but I trust them).
So there's a new one going in this afternoon. Hopefully that will resolve it.

 

[jberks]

Final Update - Hopefully.....

They replaced the battery control unit as it refused to take any updates. The alternator was kicking out all sorts of current levels and apparently the reg isn't replaceable on that one, so a new one went in. Took the car home and the parking sensors and radio stopped working. Interrogated it again and found the bus gateway to be playing silly buggers and refusing to talk to the Audio gateway or parking sensors. Reset ok but this kept happening so it was replaced too.
All this explained a few problems but not why the original battery went flat so they had another go. Sure enough, current drain was nominal on test but since it had become the car from hell, they kept at it and after 30 mins or so, it suddenly jumped to over 1a.
Long story short (1 day of diagnosis later) - it was the switch panel that sits in front of the cd changer. So we now have a new one of those.
Fingers crossed .......

Hopefully this saga will help others ..

 

[jibcl500]

Wouldnt it be good it Mercedes had a RJ45 socket on the car so you could go outside with a wirless laptop pulg the RJ45 into the car, goto to a Mercedes web site where it checks to see if your car has the latest software updates and if not downloads them to the car etc.

It could also report back to MB any errors andupdates done etc.

I think im onto something here. Any techies here want to be a director??

jib

 

[jberks]

didn't the McClaren F1 have this? A modem jack under the bonnet to dial into the factory. It won't be long until all cars have wireless internet, then there'll be no stopping them. Just a little 'update' icon flashing up on the dash. Then no doubt, cars will get virusses and there'll be Norton for BMW"!!
If my PC is anything to go by, it should slow the buggers down anyway!!

 

[television]

didn't the McClaren F1 have this? A modem jack under the bonnet to dial into the factory. It won't be long until all cars have wireless internet, then there'll be no stopping them. Just a little 'update' icon flashing up on the dash. Then no doubt, cars will get virusses and there'll be Norton for BMW"!!
If my PC is anything to go by, it should slow the buggers down anyway!!

The latest diagnostic devices fit in the socket when you drive, then you just plug the thing into the tester and all the faults have been recorded and time stamped

 

[pomm001]

w211 Warning message and cons swithched off

Having read some of this thread i am now quite worried
my 04 220 e class has been shunted around quite a lot over the weekend ignition on with auto lights on etc.
Come to start this morning and it spins up as normal, but starts with one cylinder out and the message consumables swithched off.
Not wanting to run with one cylinder out ,was just about to swith off and it picked up on 4 pots , cons light warning still up.
Had to go to work but after a few minutes evrything came back up as normal .
I am guessing that although the battery is turning the engine over OK it may have a little too much current drop triggering the warning on the dash, i guess it the original battery which is coming up to 4 years old but does anyone have any idea if this could give me the misfire ?which has never done before ?
Also if i am to replace the battery are there any special precautions so as not to loose all settings, will i need one of thoes plug in to the cigarette lighter code saver gadgets.
all advise gratefully recieved

 

[jberks]

I wouldn't go changing anything yet. It may just be that you've run the battery down a bit.
As far as a cylinder down is concerned, yours is a diesel so low power won't normally cause a missfire.
It's more likely that you either didn't give the glowplugs long enough as they were taking longer due to the lower voltage, or there wasn't enough juice to get them up all to temp initially. Once the engine warmed up a little, the cylinder will start to work properly and all will be well.(as it was).
If in doubt, pop a battery charger on it overnight.