americanyankee

Hello Gents:


My 2006 E350 wagon seems to have intermittent battery drain after it is parked.


I don't drive it that often two or three times a week. Some days when I first start it, I get a message stating convenience features unavailable due to low battery. I drive for about a block and features come on.


I recently was away for eight days and was worried that battery might be dead. It started right up with no messages. I drove it that day, parked it,
and the next morning the low battery message was on .


Anyone out there have similar problem?


Anyone have any idea what could be wrong?


Thanks for any input.


Cheers

2.7Tallroader

You may have to check the battery and the alternator. In my case, the lights that were on were pulsing at times so I replaced the regulator on the alternator. I checked the battery but it was borderline, so I kept but a few days later it died. I replaced it with a DieHard AGM battery from Sears (purchased from the web, with in-store pickup- cheaper than buying from the store). Now, everything is fine, no more "convenience function unavailable" messages.

You can check the voltage by putting ignition in Position 1,make sure the IC displays the Speed, and press the reset button on the left of the IC three times. The voltage should appear.

americanyankee

Hey thanks very much for your reply. At least I have enough info now thanks to you, to narrow down the problem.


Cheers

dave2001auto

Cheapest fix are case by leaving something on:
On an older MBZ wagon someone would leave the rear tailgate door light on. The light is not very noticable in daylight nor night time. Your could check the drain with an amp meter. I need to preload the computer circuits before the amp meter will give a good reading.

( - of battery) to (AMP meter shorted) to (- of ground) Let the electronics stability.

remove the short from the AMP meter. Have meter on high amp setting at first. Then switch to lower ranges. Reads a pulsating value of about 5mA to 40mA. Without the shorting, my meter just gets too confused to give a reading due to the high inital current and all the pulses.

If you meter will record the min. and max. reading, let if find the high reading. Then is elimination by looking for light that are on, then pulling fuses.

Check your charging system using a volt meter. Some cheaper volt meters can be almost 1 V off at 12V, so unless you have an accurate volt meter go by the difference in readings. Measure battery voltages. At rest. Turn on headllights and remeasure, Turn off headlights and remeasure. Difference between last two value about <0.5V Check battery if more than >0.5V on a fully charged battery. Start engine. Voltage should be about 14.3 V. Turn on headlight, HVAC fan on high, and see if voltage can be maintained at 1500 rpm. If not check charging system with the engine off, cable connections, belt, etc.

There might be an internal short in the battery that my come and go with a lose grid/plate. Batteries only last about 3 years with hot summers.

Driving 3 X a week for 15 minutes each time is usually good enough to keep a battery charged. Lots of people do it every other week.

john0183

Check your bcm battery control module I had the same problem with mine 2003 e500 and it fixed it because my battery would drain over night or even driving just to the corner store .i am no mechanic just from my experience . Maybe that helps good luck.

americanyankee

You the man. You were absolutely right. I I checked my rear interior lights and found one on. Three days now and no battery drain .
Thanks for your help!!!!!


cheers

dave2001auto

americanyankee,
Glad you found it was the cheapest problem to fix. 0 cents. It can also be accidential turned on from the front of the car too.

For me, the rear interior light was more trouble than what it worth. I disconnected it and had a LED flashlight in the car. Much brighter and no dead car battery. It can also be accidential turned on from the front of the car too.

americanyankee

Thanks again Dave for your solution: I think I'll let the rear light live unless it happens again, then for sure it's LED time.


Cheers

mtrevelino

Shouldn't the CAN BUS shut off all interior lights after one minute? I notice that if I leave my trunk open the light will go out after a couple of minutes.
Mike T.

americanyankee

Not sure what you mean about CAN BUS however, Whatever button I pushed, seemed to have worked because I no longer have low battery warning.

mtrevelino

The cars computer (CAN BUS) should shut down all electronics after approximately one minute. Even if you leave a door open, the interior lights will go out in one minute, at least on my cdi they do.
Mike T.

americanyankee

I see what your saying Mike. It makes sense.
What doesn't make sense is I pushed my light switches on and off including my phone connect ,and today is the fourth day I drove my Benz in a row with no low battery warning. Next time I'm in for service, I will talk to tech about it. I'm a little mystified about it ,but happy at the same time because battery drain seems to be gone. Many thanks for your thoughts






Cheers