Beemert

530xi 2006

was testing my spare key, put a new battery in it, while I was driving the key and battery fell apart, and immediately an error popped up on my dash “fob battery separated from key, do not turn off engine” I tried to put the key back together when turning off engine, ignition is now locked, my main key I will try tomorrow don’t have it currently, I have already tried to move steering wheel while turning key, it’s in park, can’t Jimmy the thing to turn the ignition is just straight up locked. Any ideas ? Should I disconnect the battery try to reset the computer in it or something?

twh

Diamond key or rectangular key fob?

Beemert

diamond key fob, used my main key last night and the ignition unlocked. Very weird, I’m assuming I broke the transponder in my spare key or something? Not too sure this is a weird one. Think my spare key is toast

twh

Haven't experienced this particular message. I do have the same car and key type. Recently needed a new battery.

When you say you put a new battery in it, how did you proceed? Did you desolder it and solder a new rechargeable battery in? Was it the right type? Did you mess up any other parts of the little circuit board?

Beemert

yeah no me neither, was very surprised by it, wish I coulda gotten a picture, I’ll maybe try again see if I can get the error, I’ll keep you posted…
but so basically dismantled the key, desoldered the old battery and then resoldered a new battery I bought online, was the VL2020 ML2020, I’m assuming I must’ve damaged the transponder or something on the motherboard hence why it was so finicky when I was trying to get my car started the first time when this all happened with the spare key,

long story short, was sorted by using a functioning key, so I must’ve damaged something on that spare key… none the less very interesting though haven’t seen anything like it before

donpb

A new key fob can be pricy. I'd suggest you to carefully inspect the PCB for any minor damage. Hopefully there was no ESD damage or else you're screwed. Also, verify the battery voltage and polarity.

twh

I would think that key should work without a battery. So, I don't fully understand the message.

Now, if the transponder ID chip got messed up after starting, that would prevent if from starting the next time, but if it is already running, I'd imagine it to stay running until turned off.

You said "ignition is now locked,...I have already tried to move steering wheel while turning key, it’s in park, can’t Jimmy the thing to turn the ignition is just straight up locked". Does that mean that with the physical part of the key in the ignition, you couldn't turn the key in the cylinder? If yes, that is strange. Unless the physical key blade is damaged, that should turn the cylinder no matter what. I don't think the transponder has anything to do with that. The car will just compain that the key transpoder doesn't match what's in the car.

Echoing what donpb says, these are not cheap and now you are down to one. You should fix it.

donpb

2006 530xi has an ignition cylinder to turn? My 2006 530i does not.

The physical key only operates the driver's door, glove box and trunk cylinders.

twh

They changed from diamond key to rectangular key fob mid-year production - at least as far as the US cars are concerned. There was a major change in many electrical things mid-year. For the key, I think the cutoff was production up until 09/2005 used the diamond key. My car is production 06/2005 and has the diamond key.

donpb

Yeah that's what I figured, the infamous mid-year changeover. Mine is 11/2005.