[hecticbimmer]

Hi guys, i will try my best to explain what’s going on in as much detail as possible in the exact order these events occured. I have a 2015 330i m sport.

Edit 1: Error codes, cdb804, cdb309, cda507

Yesterday i came home from work in my car to quickly change for gym, when i got back to the car and started it again i was met with the lighting system error. This meant my back indicators, back windows, and trunk weren’t working. The indicators on the mirrors/dash were also rapidly flashing. I continued driving and then later on that night after researching i tried disconnecting my battery (-) for a few minutes and then connecting it again however that didn’t fix the issue.

The next day i started the car and the same thing was there but oh well i started driving to work, maybe about 3 minutes into driving my music stopped playing and i saw that my idrive system went black, next the car threw up another lightning error and this time my front headlights, high beams, front indicators, air conditioning, idrive, all went out.

I have tried disconnecting and reconnecting the battery a good amount of times (i have to climb into my boot by putting the seats down as the trunk won’t open), left it for hours then tried again. However it’s always the same outcome, i start the car and nothing works. The idrive starts up, shows the error for a few seconds then goes off. im met with all sorts of cels, sos failing, lighting system, sometimes after i connect the battery it’ll say battery discharge.

Now, i would also like to point out another issue which is my left headlight (passenger side, im in australia) has a little chip in it which has been causing condensation in the light for about 2 months, it is REALLY bad when it rains and i’ve never gotten around to fixing it. Is it possible water could’ve gotten into my FEM from the left headlight? I know that most likely the reason all of this is happening is because my FEM is fried, maybe even the REM too as the back half of the electronics went out first and also when i bought the car in july 2023 it came with the parking sensors not working it gave the parking assist error.

Anyways, what do i do. How do i go on about fixing this? i’ve got ista+ currently downloading so i can see what it specially is but guys i’m so lost where do i go from here. I’m 19 years old this is my first car and it’s heartbreaking that this has happened because i know it’ll be expensive and frustrating.

Also if it is FEM, where can i buy one? Google is showing me nothing, and then how do i install it? Would it be plug n play?
Also where tf does the REM unit go? I’ve found one online that i can buy, is that also plug in play?

Im just so confused maybe the whole issue is just a battery needing to be replaced idk any help would be appreciated guys.
i will attach any images that could help.

TLDR: Headlights not turning on, high beam not working, back indicators not working, front indicators rapid flashing, idrive not working, back windows not working , trunk not opening,

[Billfitz]

Water can't migrate to the FEM from the headlight, but short circuits in the lamp could cause FEM problems. As is always the first step with anything electrical you need to pull codes.

[hecticbimmer]

Originally Posted by Billfitz

Water can't migrate to the FEM from the headlight, but short circuits in the lamp could cause FEM problems. As is always the first step with anything electrical you need to pull codes.

Hey bro the error codes are cdb804, cdb309, cda507 from what i can remember, i’ll check again tomorrow

[Billfitz]

When you have the codes google them, prefaced by 'BMW'.