Hi there

Is there anything I need to be mindful about when replacing the consumer battery?
As in, I just need to disconnect the -ve terminal first, remove battery, replace, attach the -ve terminal last?
I'm intending to use a Varta A5 battery.

Thanks in advance
Nigel.

 

Yeah is really is that simple on a w221.

 

NOT quite so simple - if you want to get things right

make sure you don't get the silly positive cable touching anything - its connected to the front battery

1) the alarm may sound taking off the battery - if so reconnect and unlock all the doors, then disconnect
2) it makes much more sense to carefully disconnect this short positive lead from the power management module above the battery and from the battery - as you have more room to work
3) don't forget to detach the breather elbow on the right hand side - its wiggles out sideways towards the inner wing - more importantly refit to vent acid / gases to the floor outside (all easier to reach without that silly power cable in the way)
4) slide batteries in and out on a bit of plastic, helps slide on the floor carpet
5) on reconnection - the interior clock should pop back to current time - but if its never been off before it may not
6) re-set anti-trap on all four door windows and the sunroof - open fully close and hold till you hear a faint clunk - note the sunroof needs both tilt and open reset - miss this and one touch open close won't behave

when all done - check the car's date in comand settings - when you see that says 2003 come back and we'll tell you how to fix the cars brain with a cd based comand update - its particularly useful to fix if you use daylight saving in your area and or you want the time of arrival on the Nav to make sense - (it might say 2005 by now)

.

 

yeah, not removing the positive terminal lead makes it hard to get the breather back in but it's done.
date and time both reset to 12.00 1st Jan 2003. I manually reset them.
I tried resetting anti trap on the windows and sun roof but I didn't hear any clunk but I had driven the car to work by then so I'm not sure what happened there. one touch close on the sun roof seems to work tho.

re fixing the cars brain, what would i be fixing at this point? are you implying I've lost any updates that were applied to the car already?

thanks for the advice Botus, much appreciated.

 

what you say almost doesn't make sense - till I figured you may not have Sat Nav on this car. If you have Sat Nav you shouldn't be able to set the time or date....

Re. your concern about "missing" updates - nope its far more likely it never had it - so long as the battery had never been off the car the year was remembered

1) did you actually go back and see if the date you set worked... you can play but it should never accept the change...
2) the clock can play games and sometimes seems to work - usually getting more confusing if your area uses daylight saving and you are in saving period

please check if the date you believed you set actually happened (I expect not) if it did do you have Sat Nav on this car?
another bit of fun was the car outside when you were working on the car ? (if in a deep well constructed underground car park you'll sometimes temporarily get get other results...)

All this fun came in April 2019 when a WNRO event came about and the satellites that provide the cars time and date info went round a 19 year silly cycle - ever since the car misinterprets the info the satellites are now giving - but it can be fixed !

que lots of fun where you don't have the kit on any PC in the house - the dvd drive is worn out on the car - or you don't make the update Cd correctly

a small patch to update the comand unit (in a 8 minute fix) was made by a forum member Polar Bear... then I fixed a small bug stopping a number of mid 2008 comand units updating, in a later Cd

read posts from the following link

#135 - making a Cd
#264 - all the info and the later .ISO file to download

https://mbworld.org/forums/s-class-w...ml#post8468441

ENG Menus
get in the car and turn on the key (it can ALL be done with it running - they flatten batteries in seconds on these cars otherwise)...
move the comand cursor (which Icon is highlighted) on the top menu bar that reads Navi, Audio, Telephone, Video, Vehicle,
use the control wheel to select Vehicle. Then pull the control wheel to the bottom menu and highlight System Settings

now these four all have to be done together

o Press and hold the “*” button, which is referred to as the “Favorite” button and typically actuates the rear sunshade.
o While holding “*”, press the Control Dial to the Right without pressing it down or turning it.
o While the “*” is pressed and the Control Dial is held to the right, press the Seat Massage button to the right of the Hazard switch and hold it.
o While holding the “*” button, the Control Dial to the Right, and the Seat Massage button, press the Mute button, which is the button located below the VOL dial and has an icon of a speaker with a slash.

 When this combination is performed successfully, you will have reached the Engineering Menu.

change NOTHING other than instigating update if you have fitted the right clock fix CD in the drive - but you can safely scroll round to look at everything
the back arrow key (one of the buttons around the comand knob switch panel), or key on off, will take you out of the ENG menus

 

ah, this car does have sat nav but there has always been something not quite right with it. if you go down new roading it gets horribly confused and take a very long time to correct itself. maybe the aerial has an intermittent issue, idk, never bothered looking into it as the phone is so much better.
i was working outside on the car but way out of the city, i've always wondered what the satellite coverage is even like here in NZ now, maybe it's just really intermittent.

i've set the clock before and it's stayed, lets see what happens this time.

re the satellite bug fix, yeah i've read that post previously thanks, I'll give it a go if and when I get a chance. and that depends on whether or not replacing this battery cures the set of random error codes I've been getting. (previous battery was way too small, thanks previous owner)

 

I hope its a factory NZ car not a nasty Jap import... Japanese cars used a hybrid mess up of locally sourced in car entertainment.

The Nav antenna can fail on Merc cars - but the 221 version is far better than many other models - they fail lost getting no signal.
If the mapping is miles out of date and the clock is helping confuse the car that would tend to make it lag.
Maybe you get less satellites down there to help it know where it is - one device I have finds 16 quickly...

 

NZ new, don't think I could deal with a japanese import version.

Is there a way to tell how many satellites it can see? what device do you use to do that?

 

..that question likely comes round to are you running NTG3.0 on last software for the comand, or the later NTG3.5 - July 2009 build cars moved to the later better lookalike comand system...

if the earlier NTG3.0 system - of the selectable options when using Navi (along the bottom of the screen) - one is to show the number of satellites available (picture below shows 10 visible, I usually see 7 in S-East UK) - whether this option exists on the early iterations of scrambled jokeware the car was sold with I don't know.

Certainly if you go to map views and see if it displays "Bird's eye" view option, aka leant over proper 3D display - showing sky at the top of the screen. Then its running the last comand update - then you definitely get "show the number of satellites available" or "GPS coordinates" or the useful "time of arrival" (plus that update that gives tweaks to, or in USA turns on, delayed traffic info services.

see section bottom right (point 2)

 

Recently took mine out to charge (Noticed my voltage was reading 11.7V overnight)

When the battery was removed I went to workshop menu and went to “vehicle information” and noticed it still was reading 11.7V.

The dash loss power of course since the trunk battery was out and on the charger and everything went dark.

I decided to push the start button again and the dash lit up and I again went to the workshop menu and the voltage was still reading 11.7V but dipped to 11.6V before everything shut down again.

This made me wonder “Is the voltage info on the dash measuring the starter battery under the hood?”

I was always under the impression the main trunk battery was the voltage being shown but how could this be if the battery was completely out?

 

(for early cars) both batteries are linked and are charged by one alternator - the volts at the CGW diagnostics socket are not the same voltage much of the rest of the car sees - the cluster toy is likely just that - there is so much electrical stuff and so much canbus detritus - keep BOTH batteries in perfect shape, drive it regularly, keep the sunroof & windscreen drains clear and underneath the carpet bone dry

 

So the voltage number we get on the dash is NOT solely reading the battery in the boot but also the starter battery and giving the average voltage between the 2…correct?

For example,
starter battery under hood=11.5V
trunk battery in trunk=12V
dash reading=11.75V

 

no idea its probably just made up from the nearest 12V idea it has to look at - from all the crap varying volts somewhere in the car


my diagnostic socket reports 2 volt lower than the car is really at - swap to a later CGW its exactly the same

 

Ha, yeah very definitely the earlier version of NTG , probably I'll just keep it like that, goes with the car I guess.
I think this is a very early build car.

thanks
Nigel.

 

fix the date - and see if the GPS becomes more responsive - the date also messes up the service schedules

 

ok, thanks, I'll give it a go, may take a week or two to find th time right now to attempt it.
will report back.