mrreason

Hello all,
First time posting thought I should get some help with an issue I having for about 6 months. My 09 S550 was fine, took to get smogged and all heck started. Couple day after smog, white charging light came on. Took vehicle to 2 independent MB shops here in Lancaster, CA. Both say battery, alt was fine, They say had to take to dealer to upgrade software to clear codes. Called dealer they say what software ,no updates. Shops seemed good both were referrals. One shop say ok to drive as everything system was charging. He replaced both batteries. Light not off, Now says something about recall on instrament cluster as malfuctions incorectly shows not charging when it is. MBZ newbie here...any help or suggestion greatly appreciated.

konigstiger

SA should have checked Vehicle Master Inquiry (VMI) to see if there are any outstanding Service and/or Recall campaigns for your VIN. Software update suggested by independents may have already been applied if applicable. In example found attached service campaign that may or may not be applicable.

BOTUS

is it a facelift car (different tail lights) ? if so its normal - its come up on this forum a few times this year no one ever came back to say how it got fixed.....

dealer telling you there is no software updates is normal there'll be 30 to 60 individual modules that could be updated - each one at a time... at massive time and cost - some would be useful / some might be necessary - no dealer could ever tell which is which - they don't care and don't know - so its easier to tell you to go away - remember these stopped production 10 years back and the dealers mostly wouldn't even know how to drive it in the workshop safely

mrreason

From what i have been told it is a "facelift car" as it has the big battery in engine bay and the small aux bat in dash.

BOTUS

- yep then u are not alone they all do it - I don't know why - from a thread on a UK forum I found a post I'd written 4 years a go still never seen anyone say how they fixed it - there's a mega long thread on here from 2015 no one ever said what - but benz ninja seems to say flash a control module - that makes much MORE sense as indy garages mostly can't - so likely a trick merc built in to later cars

I was at an indie in the spring, some bloke with 2011 or 2012 a v8 turbo w221 had just fitted a main battery to fix same issue.... it didn't help. Put on STAR and decided the other battery was at fault. Fitted genuine Merc second battery fault still present.

After much scratching of heads they decided it was control module at fault...

JohnLane

Logical follow up questions being.... Did that module get replaced? Did that solve the problem?

BOTUS

most seem to think the control module replaced sorts it - but no one every confirms it - BUT of course the software in a new unit will be the later iteration so its not surprise it helps....

so it could well be a "mistake" in the the software on a given vehicle, that "unfortunately" makes a light come on - the owner goes to a dealer - dealer charges $240 diagnostics, in a job that takes 10 mins to get the car in the workshop, 25 seconds to run diagnostics, that they don't even run.... because they know what to do - so they flash the offending module in 3 minutes, then clear all faults and hand back the car after a leisurely 30 mins total workshop time.... including a coffee, and you pay $300 and half a day off work to achieve it

JohnLane

This implies that software programming has got to be much faster then last time I was at it. Admittedly that was 2015.

Certainly it pays handsomely to have an ‘in’ with Mercedes should such pains in the rear happen.

BOTUS

they have to keep you waiting for at least 3.5hrs - its only 30 mins to do the job, then an hour pretending to do the paper work to make it seem value for money - then the other 2 hrs "might just be" government mandated opportunities to spread covid / misery and make the ba*****ds waste half a day away from work