Bad Alternator?

carbonM · 07-02-2018, 10:31 AM

My check engine light came on while driving. But didn't see any operational issues. So when I got home I hooked up ISTA and got a lot of electric related fault codes. (see picture). Name: IMG_20180630_233618.jpg
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Name: IMG_20180630_233618.jpg
Views: 426
Size: 136.9 KB

I unlocked my cluster to check the voltage and found while the car is running I see 12.3 - 12.4 volts, which is low.

I replaced and registered my battery about a month ago because I was getting the increased discharged error. Which seemed to fix the error.

Seems like the alternator might be the issue but before I replaced it wanted to get others feedback.

0-60Motorsports · 07-05-2018, 02:09 PM

I had the exact same thing happen twice on the X5M. the first time the battery was replaced as it was 3.5 years old an bulging at the sides

today i replaced the alternator as we still had the BHD error showing up. Hopefully that fixed the issue. Will find out on Saturday

philly42 · 07-05-2018, 04:11 PM

It seems that it might be the alternator. I got a bunch of malfunction errors too which turned out to be an alternator issue. I remember finding different voltage readings when I called up the DME ecu. Though I got the voltage readings using a volt meter at the battery.

If you have a volt meter, run a test at the battery. Test the voltage at idle with low load. Then run the same test with high electrical load. Turn on and leave on as much electrical components as you can.

From my understanding, a common problem is the voltage regulator on the alternator. Some people just replace that. I replaced the alternator in its entirety given the amount of work needed to access it.

07-02-2018, 10:31 AM	#1
carbonM Private 13 Rep 67 Posts Drives: 2011 E70 50iMt, 2011 e82 135i Join Date: Nov 2017 Location: Texas iTrader: (0)	Bad Alternator? My check engine light came on while driving. But didn't see any operational issues. So when I got home I hooked up ISTA and got a lot of electric related fault codes. (see picture). I unlocked my cluster to check the voltage and found while the car is running I see 12.3 - 12.4 volts, which is low. I replaced and registered my battery about a month ago because I was getting the increased discharged error. Which seemed to fix the error. Seems like the alternator might be the issue but before I replaced it wanted to get others feedback.
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07-05-2018, 02:09 PM	#2
0-60Motorsports Brigadier General 792 Rep 3,151 Posts Drives: BMW M3 JB 04 Coupe Join Date: Aug 2007 Location: Kingdom of Bahrain iTrader: (1)	I had the exact same thing happen twice on the X5M. the first time the battery was replaced as it was 3.5 years old an bulging at the sides today i replaced the alternator as we still had the BHD error showing up. Hopefully that fixed the issue. Will find out on Saturday __________________ Current Mods: 2004 E46 M3cs JB/CSL 2010 E70 X5M AW/BLACK 2011 VW Golf R DSG White/Black IG: @060Motorsports
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07-05-2018, 04:11 PM	#3
philly42 Second Lieutenant 93 Rep 291 Posts Drives: X5M, Z3M Join Date: Mar 2016 Location: Dallas, TX iTrader: (0)	It seems that it might be the alternator. I got a bunch of malfunction errors too which turned out to be an alternator issue. I remember finding different voltage readings when I called up the DME ecu. Though I got the voltage readings using a volt meter at the battery. If you have a volt meter, run a test at the battery. Test the voltage at idle with low load. Then run the same test with high electrical load. Turn on and leave on as much electrical components as you can. From my understanding, a common problem is the voltage regulator on the alternator. Some people just replace that. I replaced the alternator in its entirety given the amount of work needed to access it.
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