Hi everyone!

I own a 2004 530i with about 116k miles on it. Been having issues with the car lately when starting, it happened when I was changing the angel eye bulbs (OEM) and it died on me. Started right up after a boost but since then it has been dying on me (luckily at home only). For a few days in the mornings, the first start is VERY rough and takes it several seconds to turn but today I went to start it and its dead. I had noticed with my little Bluetooth plug-in that gives out battery voltage readings, it was around 8-9V with those rough starts. Eventually after a few starts, it would be around 12V.

The car clicks and the dash lights come on, as well as the iDrive, but the engine doesnt turn over. After a while, it completely dies and doesn't click. The battery was replaced EXACTLY two years ago and just this past summer the IBS sensor failed and I replaced that, the car still does go to sleep so I dont believe it failed again. I did my fair share of googling but confused as to what it could be at this point. The car does not sit for weeks without driving, it is driven at least 3-4 times in a week.

Any thoughts would be appreciated, could it really be the battery? I will see if it starts up again with a jump tomorrow otherwise it'll have to be towed on Monday to the shop.

I also received the yellow battery icon in the dashboard, just an fyi.

 

You need to have the alternator and battery checked out. The battery light is for the alternator. 9v is nothing. How old is the battery?

It's either the alternator not charging or your battery is dead. Could be both depending on how old the battery is or how long it's been happening

 

I just checked my records, the battery was replaced (and registered) in February 2019 actually. Since it'll be two years in about a few months, would the alternator be at fault? Would there be a way for me to check if its the alternator? I used a multi-meter on the battery just now and it came at about 9V (before unlocking the car) and went to 8V after unlocking it.

 

My bet its the battery especially if you've never registered it. First check the alternator output, charge the battery and then load test it.

 

The battery was replaced and registered and since then was working fine (until the IBS failed which I replaced in May, caused no issues until now). How can I go about checking the alternator output?

 

Do you have a OBDII reader that can load test. Do you have a battery charger? You can also go to advance auto or another store to have them test it if you can make it if not take the battery out and take it to them to charge it up. Install it and then take it there to have them load test it

 

Luckily I have two cars or else you'll have to wait there for hours. I already knew it was my battery but they had to prove it to themselves in order to honor my battery warranty. Dude said the battery was fine until I made him do a load test.

If the IBS was acting wonky, it could have ended up eventually damaging the new battery.

 

Get it started then put your multimeter over the battery whilst it is running, You should have a Minimum of 13.8 Volts. If less than 12V start at the alternator and work back.

 

As a response to everyone that has graciously put their suggestions, I got it started a few hours ago. The battery stayed at around 14 volts with the engine running and with a load on(lights, radio, heating, etc,) it was about 13.7-13.9v or so. I used a OBDII reader that got delivered yesterday and I plugged it in to get these faults, does anything stand out from these screenshots? I plan to take the battery to a local store to get checked but with these voltage readings, it seems like the alternator would be okay?

 

Get the battery checked, especially the load test.

The load test is supposed to be run without the engine running. If you had load test voltages that high, the engine must have been running.

When your battery is acting up, its common to trigger a boat load of codes.