openinverter forum

Thank you all for letting me join.
My wife and I bought an 2014 bmw i3 from a repo auction.
Once I got the car home and hooked up to Ista +, I saw that the VIN in the BCM differs from the cars VIN on the frame and paperwork.
I appears someone has swapped in the BDC from a different i3 and didn't code in the FA or register the correct VIN to the BDC.

We managed to code the right vin to the BDC and straighten out the FA. But the car will not move , IMMO is activated I believe with an error.
21E921 electronic Immobilizer: non authentic response received.
what to do in order to get the ISN (I presume) in the EME changed to match the request from the BDC?

Or what do we need to do in order to remedy this?
thank you, and I know its a deep dive for a first introductory post.

NE555 wrote: ↑Sat Nov 22, 2025 4:02 pm ... But the car will not move , IMMO is activated I believe with an error.
21E921 electronic Immobilizer: non authentic response received.
what to do in order to get the ISN (I presume) in the EME changed to match the request from the BDC?

Or what do we need to do in order to remedy this?
thank you, and I know its a deep dive for a first introductory post.

You may get better help on a BMW forum. Ze Germans immobilizers can be a pain to work through.

This thread seems to have similar struggles, https://openinverter.org/forum/viewtopic.php?t=5064

I actually came from a bmw forum and on these forums it is difficult to weed through the ‘charge/change out the 12v battery’ posts and reply to numeous 12v battery replies without offending anyone who doesn’t read the last 20 thread messages mentioning 12v battery.
So I’m honestly hoping to get better suggestions here.

You may get better responses from forums that use expensive tools to hack this kinda stuff. Like MHA auto and similar ones. I wouldn't expect the solution to be cheap though.

This issue sounds similar to VW's component Security. Where if you swap something something simple like the comfort module that regulates windows and whatnot you will not be able to extract the pin code required to learn a new key because they split the key and put a part in the cluster another somewhere else etc.

If that is the case for you then you only have a few options left like a BMW dealer or immo delete. I've not really seen many or any real immo bypass or deletes for EVs though.