2009 Wagon Dies
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Junior Member
Joined: Nov 2014
Posts: 57
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From: Savannah, GA/Mystic/CT
2009 E350 4matic wagon, 1980 450SL, 2011 GL450
2009 Wagon Dies
I have a 2009 e350 4 matic wagon. It was in storage for 3 months and I had to jump start it upon return. It turned over slowly but was fine once jumped. Ran a few errands and parked it for a day. Started up fine this morning and drove about 3 miles. I let it idle a few minutes while I was on the phone and then the engine died. I turned it off and came back about 5 minutes later. Turn the key, all the dash lights came on, radio came, windows work, but nothing when I tried to start it. Ideas?
Out Of Control!!
Joined: Apr 2019
Posts: 12,253
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
SELF INFLICTED PAIN
What happened is you used ALT to recharge your flat batteries.
So over 100A had plenty of time to fry up something along the way to charging battery: ALT, SAM or BCM...
Do you have an AUX batt in the dashboard side??
> NORMAL PROCEDURE:
To prevent this NEVER JUMP A FLAT/dead battery.
Use a battery charger overnight on low batteries
A recent battery run flat is as good as dead.
ALT only regulates voltage. It can not regulate current : 250Amp Max
ALT puts out as much current necessary to deliver 14Volts.
Flat Battery will get overheated by 1,500.Watts of power... ouch!
Last edited by CaliBenzDriver; Apr 9, 2025 at 06:00 AM.
Member
Joined: Jun 2024
Posts: 191
Likes: 58
E320
That definitely sounds like a weak battery or possible voltage drop issue that’s affecting the starter circuit. When a car sits for a few months, the battery can lose a lot of capacity even if it seems to recover after a jump. The fact that all dash lights come on but there’s no crank usually points to either low voltage, a bad battery cell, or possibly corrosion at the ground or starter connections. Also wouldn’t rule out a failing starter relay or EIS (electronic ignition switch) if it’s intermittent.
