[335iGabe]

HELP PLZZZZZZ ,So I recently just picked up a 2008 335i with 130k miles and battery light was on the day after I bought it so I changed the battery 5 days later keep in mind the 5 days before I didn't even drive it much then when I replaced new battery I had to get it registered and coded in at a local mechanic because my pro-tool app was acting up so he registered it for me he mentioned a alternator code kept popping up he said it could be cuz of the new battery that it would take time for car to recognize the battery when I was driving home I got a plethora of lights check engine, automatic gearbox trans light and I think I saw a abs light too I freaked out and when I got home I turned it off and turned it back on and the check engine light came on and I would only get trans light when I'd hit 2k rpm then today I came to my car to see what was up with it and it's completely dead brand new battery too so I just unplugged the battery just Incase I'm lost and need help or an ideas on what to do I just got into cars so I'm kind of a newbie but I'm just freaking out Ik n54s were unreliable but not this much please help any comments would be much appreciated have a great day stay safe !

[sdbmwcoding]

Replace your alternator

[BzsBimmer]

Take battery out and take to autozone or something similar. Have them read the battery.

If the battery is dead, replace it. If it just needs juice, they can charge it for free.

If your mechanic said there are alternator codes, maybe the alternator or voltage regulator is toast.

The battery is only used to start the vehicle. After that the alternator takes over and the battery becomes a load to the alternator. If your alternator isn’t working, it won’t charge your battery and the car will only start so many times before battery drains.

[BzsBimmer]

Once you get the car back running, take it back to Autozone or similar and have them scan your alternator as well.

[335iGabe]

Originally Posted by BzsBimmer

Once you get the car back running, take it back to Autozone or similar and have them scan your alternator as well.

Will do thank you so much just crazy to think ina take the battery they just sold me 3 days ago lol

[ctuna]

Your better off putting this in the general section rather than the
bluetooth and audio section.

https://www.e90post.com/forums/forumdisplay.php?f=2
https://www.e90post.com/forums/showthread.php?t=1517476

There are many battery problem electrical problems as related
to the motor there.
Other things that can cause this problem .
Bad ground strap to motor.
Parasitc drain due to anything but aftermarket equipment
can be part of the problem.
Car does not go to sleep due to various reasons.

Also measure the resting and running voltages at various points in the car
with a multimeter.

Good resting battery voltage 12.4 to 13
Good running alternator voltage 13.5 to 14.5

You will get all kinds of false error's with a low battery .

electical e90 pdf
http://www.google.com/url?sa=t&rct=j...,d.cGU&cad=rja
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU
http://www.google.com/url?sa=t&rct=j...85464276,d.cGU

If you didn't do your research you maybe have bought a money pit.
You need to learn to DIY on these or they will drain you.

diagnostic manual ista/inpa
https://www.google.com/url?sa=t&rct=...xo19teM9vkTF-C
https://www.google.com/url?sa=t&rct=...7x8H3pN8h1fMuF
https://bimmerprofs.com/diagnostics-inpa-part-1/
https://www.google.com/url?sa=t&rct=...lkXEhlQYy4i9Nb
https://www.bimmerforums.com/forum/s...-P-actually-do

primary links
https://www.bimmerfest.com/forums/at...9&d=1539905743
https://www.e90post.com/forums/showthread.php?t=1681573