Alternator/Regulator or Battery

F80Mmm · 01-13-2021, 11:17 AM

Went into limp mode on the freeway and car wouldn’t start and got 2 codes (2E98 and 2DEB, but fired up 10 minutes later and I was able to get home. Ran errands later in the day and car died with very little juice/screens flickering and key fob getting stuck. Same 2 codes + 2A1A, 2DEC and 2E83. So do I need a new alternator? Battery is 2 yrs old and I didn’t have any signs of it getting low prior to today.

SixSix · 01-13-2021, 10:10 PM

I would get the battery tested before making any decisions. It does sound like a charging issue due to your flickering screens and random codes. It's likely that if the battery was the issue your car wouldn't have enough power to start at all. There should be a voltage regulator on the back of the alternator that can be replaced. I've had some friends with similar issues and typically the voltage regulator is the culprit. But I would definitely suggest getting your battery tested, and if it's not faulty take a multimeter to the alternator output and see if it's putting out between 13-14.6 volts while the car is running.

F80Mmm · 01-14-2021, 08:36 PM

I got the car towed and battery is dead. I charged it for an hour and only getting 11.6 volts on the battery with the multimeter. I couldn’t even fire the car up to check to see if the multimeter spikes over 14.4 with the car idle.

SixSix · 01-15-2021, 03:30 PM

Leave a charger on it overnight if you can, otherwise you'll need a new battery if that one is toast so you can troubleshoot and figure out why your battery died.

F80Mmm · 01-28-2021, 06:33 PM

It was the voltage regulator...I'm at 98,200 miles and the 2 metal prongs were super worn down.

mweisdorfer · 01-29-2021, 12:13 PM

Quote:

Originally Posted by F80Mmm

It was the voltage regulator...I'm at 98,200 miles and the 2 metal prongs were super worn down.

The OEM battery is good for maybe 6 years or so. After that, I'd get a AGM battery.

01-13-2021, 11:17 AM	#1
F80Mmm Private First Class 72 Rep 191 Posts Drives: 18 F80 M3 ZCP, 09 E90 335i 6MT Join Date: Jan 2013 Location: Mountain View, CA iTrader: (3)	Alternator/Regulator or Battery Went into limp mode on the freeway and car wouldn’t start and got 2 codes (2E98 and 2DEB, but fired up 10 minutes later and I was able to get home. Ran errands later in the day and car died with very little juice/screens flickering and key fob getting stuck. Same 2 codes + 2A1A, 2DEC and 2E83. So do I need a new alternator? Battery is 2 yrs old and I didn’t have any signs of it getting low prior to today. __________________ 2009 BMW 335i 6MT/MHD Wedge Custom E60/VTT Inlets/VRSF DP's/VRSF 7" HD FMIC/Boost Concepts FPM-1 E85 Fuel Pump/BMS DCI/BMW PE/ER CP/Tial BOV/BMS OCC/RB PCV/19" Gunmetal Forgestar F14's Deep Concave/Michelin PS4S/Ohlins R&T Coilovers/Swift Springs/Spec Stg 2+/Icon Motorsports M3 Rep Front Bumper Last edited by F80Mmm; 01-13-2021 at 09:24 PM..
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01-13-2021, 10:10 PM	#2
SixSix Private 19 Rep 91 Posts Drives: (2007 BMW 335i E92) Join Date: Oct 2019 Location: Toronto, ON iTrader: (0) Garage List 2002 BMW 325xi [0.00] 2007 BMW 335i [0.00]	I would get the battery tested before making any decisions. It does sound like a charging issue due to your flickering screens and random codes. It's likely that if the battery was the issue your car wouldn't have enough power to start at all. There should be a voltage regulator on the back of the alternator that can be replaced. I've had some friends with similar issues and typically the voltage regulator is the culprit. But I would definitely suggest getting your battery tested, and if it's not faulty take a multimeter to the alternator output and see if it's putting out between 13-14.6 volts while the car is running.
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01-14-2021, 08:36 PM	#3
F80Mmm Private First Class 72 Rep 191 Posts Drives: 18 F80 M3 ZCP, 09 E90 335i 6MT Join Date: Jan 2013 Location: Mountain View, CA iTrader: (3)	I got the car towed and battery is dead. I charged it for an hour and only getting 11.6 volts on the battery with the multimeter. I couldn’t even fire the car up to check to see if the multimeter spikes over 14.4 with the car idle.
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01-15-2021, 03:30 PM	#4
SixSix Private 19 Rep 91 Posts Drives: (2007 BMW 335i E92) Join Date: Oct 2019 Location: Toronto, ON iTrader: (0) Garage List 2002 BMW 325xi [0.00] 2007 BMW 335i [0.00]	Leave a charger on it overnight if you can, otherwise you'll need a new battery if that one is toast so you can troubleshoot and figure out why your battery died.
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01-28-2021, 06:33 PM	#5
F80Mmm Private First Class 72 Rep 191 Posts Drives: 18 F80 M3 ZCP, 09 E90 335i 6MT Join Date: Jan 2013 Location: Mountain View, CA iTrader: (3)	It was the voltage regulator...I'm at 98,200 miles and the 2 metal prongs were super worn down.
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