My W211 has been getting the above message last winter, and it goes away after driving 2-3 miles. Recently I had the battery tested at 2 Auto parts stores and both of them said that the battery is good, as is alternator and the battery needs charged ( mind you since my retirement I just drive 5-7 miles each way). Is it possible I just drive very little and that may be causing it ? I have a charger and was planning to leave it charging over the weekend. Do I need to disconnect the terminals on main battery and do I need to disconnect the auxiliary battery ? Thanks in advance for any advice.

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06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

Did the parts stores check the auxiliary battery under the hood or just the main battery in the trunk? I was getting "battery - visit workshop" messages on the dash a couple of months ago even though the main battery was relatively new and checked out fine. The aux battery was original to the car so after 11 years (!) it was time for a replacement. Not caring to pay dealer prices, I went for the YUASA YTX14-BS battery from a large, Seattle-based online retailer and it was an easy swap, perfect fit (you just have to use the bolts that come with the new battery). Cleared up the problem immediately.

Here's a DIY with pics: DIY Auxiliary Battery Malfunction Replacement Instructions - MB Medic

I disconnected the main battery before doing the aux swap.

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

I recall getting same message almost every time I started the car no matter how long it sat. My main battery checked out OK at several places I took it to incl. a Mercedes Dealer that used a Mercedes tester.

The battery was fairly old (8 years) so I got a new one. Message went away and I have not had any other issues in 2 years.

I think batteries may loose their ability to hold a charge over time.

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-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

NH82W123. The parts store just checked the main battery. I will go back and have them check the Aux battery.

Chronometers: the car does have original battery (the car came with all the paperwork and I had the local MB adviser pull vehicle history before purchase) the history shows the battery has not changed, but does shows the battery charged in Germany; it was a North American European delivery vehicle.

Thanks for your responses and I will start calling Continental and Interstate distributors for a blemished battery and replace it.

__________________
06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

Only the main battery can trigger the convenience functions message. I used to see it when the weather was cold and the car had not been driven much in the last few days. I see the OP is in north Texas and it sure has not been cold lately so that isn't it.

When the aux battery is bad you get a red battery warning message immediately upon starting the car. The aux battery cannot trigger the convenience functions message.

I'm thinking it's time to replace the main battery. Even an agm only lasts so long.

jcyuhn: You may be right tonight it will get into 50's so I might see the sign in the morning.

Going back to original note can I just put the charger and charge the main battery without disconnecting Main Battery or Auxiliary battery? I wanted to see if I can get past one more winter out of it, as the car is driven so little. If worst scenario comes I will call Plano MB for replacement battery (I am in Far North Dallas).

__________________
06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

That's not my experience, but who knows...

I put a trickle charger on the main battery without disconnecting it or the aux when I was troubleshooting my issue with no problems.

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05 E320 CDI - 175K miles
82 300D - 200K miles (sold)

NH82W123,

I will just do that put the trickle charger, strangely this morning I did not get the "Convenience Features disabled" sign even though the temp got into 50's last night.

__________________
06 MB E320 CDI 123k miles
14 Sienna (wife's DD) 36k miles
11 GL350 Bluetec 136k (Sold)
96 E300; 292k+ miles (Donated)
11 Sprinter 22K+ miles (Sold)

That information is from the w211 service manual.

Yup, just connect your trickle charger / battery conditioner to the main battery in the trunk.

Assuming my memory isn't totally shot, the main battery is a size H8 AGM. H8 is essentially the AGM equivalent of a group 49. You can buy these anywhere nowadays, every auto parts place will stock them, so shop around.

I think this is a main computer issue- not a battery issue. I get it from time to time as well on my w211- "convenience functions temp disabled". It has little or nothing to do with the "battery visit workshop" message.

I was getting "convenience functions temp disabled" with my 8+ year old battery. Got a new one and the problem went away. I think the voltage may have had something to do with it.

__________________
-- Chris

'95 E300, 216k miles, Silver Surfer
'05 E320 CDI, 138k miles
'07 S550 4matic, 69k miles

Gone but not forgotten:

'76 300D, 350k miles?, SOLD in 1995
'75 240D, 300k miles, SOLD in 1991

My battery is newer and I'm getting that message; but I also have known main computer issues.