I bricked my car after changing 12v battery

[The-Traveler]

Forgot to disconnect HV switch in frunk. Now I can’t clear errors.

Should I try updating software using esys or just take the car to dealer.

Tried BimmerLink and Ista to clear codes. ista with enet, it complains about voltage because either I don’t have icom or the fact the fan is constantly running and no matter what I do it says it’s below 12.55v but in reality it’s 13.2.

 

[mojo]

Have you tried switching it off and leaving it to charge for a few hours? Apparently that may cause it to sort itself out in situations like this.

 

[The-Traveler]

It won’t charge

 

[EvanstonI3]

It won’t charge

Leave it plugged in for at least 12hrs, probably 24.
Yes it will not appear to be charging but for MANY owners in the past, this has worked miracles because the car slowly works out its issues with the errors in the various modules. It works MOST of the time. Not every time.

 

[3rigel]

Have you tried removing the 12v battery and fully charging it again off the car and repeating the process again with the HV disconect engaged/disconnected? This will have 2 benefits, draining the 12v system while your battery goes for a charge plus you will know you have a full battery when you drop it back in. If the eme is not charging the 12v battery for what ever reason it seems to drop quite quickly.

 

[alohart]

These spurious DTC's were probably stored when the voltage of your failing 12V battery dropped too low before you replaced it, not because you didn't disconnect the HV disconnect. Many i3 owners have experienced similar problems. Try what @3rigel suggests. It's possible to charge the 12V battery without removing it, at least on LHD i3's. Just be sure to disconnect the HV disconnect before connecting a battery charger. If the voltage of your replacement battery is too low, DTC's will continue being stored.