270 cdi elegance 2 batteries !

A9JBR

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I HAVE A 02 270CDI ELEGANCE WHICH I HAVE OWNED FOR 6 MONTHS . RECENTLY UPON 1st STARTING FOR THE DAY I GET A WARNING NOTICE" BATTERY PROTECTION AND THAT ALL FUNCTIONS ARE NOT AVAILABLE" THIS DISAPPEARS AFTER A FEW MOMENTS RUNNING. I HAVE SPOKEN TO THE PREVIOUS OWNER WHO STATED HE HAD A SIMILAR PROBLEM AND THAT LOCAL M.D. CHANGED SOMETHING ON THE ALTERNATOR WHICH DIDNT WORK AND THEN STATED IT WAS THE SECOND BATTERY WHICH THEY CHANGED AND THIS APPEARED TO CURE THE PROBLEM . THIS VEHICLE APPEARS TO BE FITTED WITH 2 BATTERIES THE MAIN ONE SITUATED IN THE BOOT AND THE OTHER IN THE ENGINE COMPARTMENT UNDER THE AIR FILTER. THE 2ND BATTERY IS A SMALL 12V MOTOR CYCLE TYPE BATTERY . I HAVE SPOKEN TO MY LOCAL PARTS SHOP WHO CANNOT FIND ANY MENTION OF THIS BATTERY IN HIS STOCK BOOKS. IS THIS BATTERY A MERC ONLY PART ? AND HOW CAN YOU TELL WHICH BATTERY IS FAILING .AT THE MO THE CAR STARTS OK AND A CHECK ON THE CHARGING RATE SHOWS WORKING CORRECTLY.
 

drmw

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Hi - surprised those more in the know than me have not responded - they no doubt will, however I'm on my second R230 (SL) which has a similar setup to what you describe - it has a smallish battery under the bonnet which is for starting only and a big one in the boot that drives all the toys. Current car fine, but last one had identical issues to what you describe. What was happening on mine was the barrage of electronics that run regardless (ie when parked) draw current from the boot battery - when you start the car, if the voltage has dropped below a certain level then the car disabled many functions (heated screen, high speed blower, roof, etc) - in other words, all those things that use power. That continued for a few minutes when driving then all back online again when the boot battery gets back up to voltage.

I had a "software upgrade" carried out for the alternator :roll: which helped a bit, but the main issue I think was the dealer who supplied it to me swapped the boot battery for a "heavy duty" job and I still suspect that because it was rated higher than the original equipment perhaps the "charging system" couldn't quite get it up to the mark.

In any event, your problem is more than likely the one in the boot - have it "drop tested" at any garage & if it's knackered, then make sure you replace with one of the correct rating, but no reason it has to be MB although I understand they can be competitive.

I'll probably now get shot down in flames for talking nonsense by the gurus but there's my three pence worth!

:D:D
 

rpe2

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If its an E class, big one is in the wheel well, the little one is under the pollen filter on the passenger side scuttle area. Take the part number off the top, or ask at your MB dealer.

If its a C class, it only has one.
 

television

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The battery set up on a 211 is very different to a 230 the 230 uses a AGLM battery for the car and in the boot, and a starter battery up front.

On a 211 the main and starter battery is in the boot and a normal lead acid type, the small aux battery up front is for the SBC.

If the car is not used much,,then the "consumers off " will come on, also if the car is driven with all things on like heated seats etc the the battery does not get much of a chance to charge fully.

On My car though it is used quite a lot, I have to charge it once a month through out the winter to keep it topped up.

The best check it to do a voltage check first thing in the morning where you would expect 12volts or more and almost 14 volt with the engine running,,it is possible that the car is not going to sleep and if this is or was the case then a voltage of 11.5 volt will be in the rear battery
 

Alex Crow

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as suggested above, you probably need a new battery, that would be the one in the boot. note that it is a 'VRLA' gel plate battery and that it should only be replaced with an equivalent - i suggest going with an MB item.

the two battery system is confusing and the official explaination documents are arbitrary at best, but the boot battery is actually used for starting - not the front one.

one more thing A9JBR, your caps lock button seems to be stuck, there is no need to shout you know :D
 

drmw

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I stand duly corrected and educated :Oops::Oops::Oops:
 

television

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I stand duly corrected and educated :Oops::Oops::Oops:

I used to think once that as the211 had 2 batteries it was the same set up as the 230,,it is only when you check that you find they are not the same
 
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A9JBR

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thanks to all responders i will take your advice on board
 

Cole@MBS

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There was a update on the software for the BCM, "Battery control module! the only thing it changed, you didnt get the message to tell you that everything was shut down!!
 

*Thumper

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STOP SHOUTING !!!!! ........ uppercase is considered shouting on a forum ........... and is 3 times as slow to read !!
 

Alex Crow

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forum ettiquette lessons.................from our resident..............wheezer:D. at least it is only 2 times as slow to read ;)

that bcm software update is about the only one our star machine prompts to install. we generally do it if needed every time we change a battery, makes sense.
 

*Thumper

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You'd better check ...... had'nt you !!

Your keyboard skills could do with a re-map !! .. tut tut !
 

jberks

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If the battery is still capable of cranking the 270 engine from cold I'd suspect its basically sound. In my experience when a battery fails its normally a cell that's gone down and it wouldn't crank. Most cars are quite tolerant of this and just crank more slowly but a merc won't even try if the voltage is too low. From the description it sounds more like a slow drain issue to me. The voltage is reduced enough to flag the warning but its fractional and a few seconds running is enough to bring it back up.

The earlier 211s (and 203s of the same era) seemed to suffer from this. Our 2002 211 did and there's been lots of posts over the last couple of years from many others with the same problem. They do drain slowly anyway so if you don't use the car much you may have the issue Malcolm has, but if its used daily then I'm not convinced.

Replacing a battery with a new fully charged one makes it go away for a bit, as obviously does fully charging the battery but it soon comes back as the current slowly drops back down. We wasted £100 on a new battery but the problem soon came back. I suspect this may be why the last guy sold the car. The dealer probably scared him with stories of £1000s for new modules so he bought the cheap new battery to make the warning go away for a bit and moved the car on. They've clearly spent time tying to fix the problem (2 repairs) but haven't got to the bottom of it. It's a simple job really but can be time consuming to track down as you need to keep pulling fuses (and know the likely culprits) until you find it.

The only way to check is to put an ammeter on the car and monitor current draw over a couple of hours after the car is switched off. As the labour required is minimal but few of us have the kit I suspect it would be a cheap test for an indie to do for you over the course of his normal working day - just popping over every 20 mins or so to see how it's getting on.

I know with ours, the problem didn't appear for around 40 minutes and hence had been given a clean bill of health twice and several innocent components had been replaced in a blind attempt to cure the warning problem - as seems to have been done on yours.

Finally we sent it in for a thorough all-day check up. All seemed well, everything shut down as normal then after over 40 mins, the current draw suddenly jumped. It appears the switch panel on the dash suddenly woke up for no apparent reason (too clever for their own good) and over a week, this was enough to drag the battery down and put the warnings on. I believe there are several modules that are known to do this too. A new panel was fitted and its been fine since.
 

television

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For the car not going to sleep ,,the battery module,OCP or a seat controller are the common faults
 

Alex Crow

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jberks had an unusual one there, very unusual for it all to go to sleep then wake up again, and not easily spotted!

had another seat controller on a clk this week, anyone have a link for the best wiring mod to power it down with ignition off (malcolm?) i know memory function will be lost but the owner understands - it is the passenger seat after all!
 


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