alexcobb

Hi to all in the forums.
I being seeing tons of people having the same issue on all forums and I see all kind of answers but nothing accurate.

My 2004 E500 star the "Battery protection Convenience functions temporary unavailable” message one month ago. I notice that even with the message I can start the car and by 15 minutes of drive the message disappear. Two weeks ago the car just doesn’t start, battery where dead. I replace alternator with a new original Mercedes one, front and rear original Mercedes batteries and replace BCU (Battery Control Unit). The car is consuming the battery on the garage. Each morning I got the Battery protection message and sometimes I need to jump the car.

Any professional help will be very appreciating.

crazypotato

Could it be your radiator fan? I read some fans come on automatically and won't turn off.

Diesel Benz

A radiator or even the heater blower would make the battery run flat in a short time (unless you mean it only comes on intermittently on its own).

If the batteries and the charging system is fine, the car probably has a consumer that does not switch off when ignition is off (as it should). There are several methods to find this consumer but first you should measure the current drain from the battery (the car needs to be fully in sleep when doing that).

vettdvr

If you disconnect the main bat. does it self discharge overnight. If so it may have a internal shorted cell.

david wenham

I run a W211 E320 CDI
For several years I have had the Battery Protection message and assumed that it was a low battery because after starting and driving for a few miles the warning would go off.
For the last three months I am now experiencing an intermittent drain from the main battery usually overnight such that the car will not start and the Red Brake warning sign appears in the dash console sometimes the boot will not open only with the key.
last August replaced the main battery with a Bosch battery and since the problem have upgrade this to MB one. Recently replaced the small "Brake" battery as this was showing a low reading. Have disconnected the seats so that are only active when the ignition is on.
Removed the fuse to the Command unit overnight to eliminate that possibility and disconnected the Tracker Unit. Problem still not solved. Garage have found drain on battery after everything is shut down but cannot identify the source.The drain is intermittent.
Read on the Forum that it could be an upgrade on the Battery Control Module so that was tried but the unit froze up whilst in connection with the computer. Have replaced the BCM.

Driving around with Jump Leads in the boot so that hopefully I can find someone who will help me jump start the car when I am stuck.

Any ideas what the problem could be????????????????

Desperate.

sebc63

I had a exact same problem when i had mine 05 E55. They replaced some module that was in the trunk that controls all the electronics in the whip. It fixed it

06e320cdi

Are you removing the key at night?

Plutoe

The drain is time consuming to locate if you do not have the tools. I would take the car to an indy with MB diagnostics. They will find the open then you can possibly provide the labor to replace the component.