Sunny 530i

so one morning i wake up to my unlock button on my comfort access fob not working, i have to touch the door handle to unlock the car, the lock and panic function work on the key fob which is weird, then i realized the trunk doesnt pop open, then i realize the interior light, wipers, rear pass and rear driver windows does not work, the rear locks does not work, have a high battery drain message, rear lamp malfunction error on the i drive, WHAT THE HECK IS GOING ON??????????

leggomysakyo

could be just a dead/dying battery. or bad alternator.

Sunny 530i

but the car fires up just fine...all other electronics work withing the car...weird

L337E60

Look for water in your trunk.

Sunny 530i

checked the trunk out and its dry, still having the same problems

leggomysakyo

take it to Sears and have them check out your battery.. They will test it for free. It could still be your battery or alternator.

Sunny 530i

sounds good, i will follow up tomorrow

IainHAustin

I had a different problem in that the computer holding the time and fuel use dropped out every time the car was switched off overnight.
But just like you the car started without any trouble.
It was the battery.
I was informed by me son that computers have a 12 volt line and perhaps the battery voltage was dropping too low.
A new batter solved the issue.

p.s. with my model I was informed that I would have to have one fitted because its perameters need to be programmed into the system.
I don't get this 'cause I reckon a 12 volt battery is a 12 volt battery.
However some people reported having problem so I got my friendly mechanic to do it.

Pretor

Im no BMW expert, so i would not know about any BMW computer issues with disconnecting the battery etc. But i am an electrican working in a mechanical workshop for all sorts of industrial machinery, so maybe i can offer some insight atleast.

Since you have a fault code i would start with that.

I would reset idrive (cd eject + dvdeject + volum knob simultainiously. (ref neat tricks thread on this forum)

If fault presist after reset:

1. Check the fuse, always check the fuse however unlikly it is as a fault source.

3. Measure voltage on battery, healthy battery should have say about 12,8v - 13,2v. With car running you should have 13,8v - 14,2v. (characteristics can vary abit, can probably find that on battery produsers website)

2. Visual check of lamp, look for bad connections, moisture droplets inside glas etc, you can smell the lamp, if a electronic component has burned out, you`ll know.. also look for soot/oxidation.

3. Measure the resistance between pluss and ground on the lamp in disconnected state. Then between pluss and ground on the cars wiring.

Example of a power leak:
If you measure, say 10 ohms between + and ground you would have a leak of 1,5 - 2 amps (ballpark have not done the math).
This would be a pretty big leak.
Your dynamo would not be able to charge your battery to more than 70-75%. If you have a 95amh (amperehours) battery for instance,this means that "fully charged" your battery would have about 70amh, if you discharge your battery under ca 30% your dynamo would not be able to recharge your battery. So you would have about a 40amh spectrum to use. Leaking 2 amps per hour would give you a flat battery in 20 hours just by being parked.
That is why recharging your battery with a charger from a wallsocket once in a while is smart, and doubly so in winter conditions! But i digress..

If you have a leak from + to ground all sorts of weird faults can manifest them self due to instability in currents delivered to sensitive electronic equipment.


Hope it`s nothing serious and that this atleast gave some insight

Sunny 530i

well i figured out what caused the issues, the body control module. I just unplugged the wires and cleaned and reconnected everything and what do you know, everything came back on lol.