[guytp]

First post and I have not been able to find an answer to this with various Google searches.

Both my 12V and drivetrain batteries were dead today. I parked the car a couple of weeks back with a low drivetrain battery and the 12V must be on its last legs as it had only just done a 10 hour drive. But it was as flat as anything today so I couldn't unlock the car.

I did the following:
1. Manual unlock door with key
2. Open bonnet (hood) manually with both 'pulls' in the doors
3. Attempted to jump start it - at this point the alarm started going off and was able to turn it off with a lock/unlock from the key fob
4. Jump start failed as the car I was jumping it from had a flat battery (good day here)
5. Charged the 12V battery for several hours until it had sufficient charge
6. Removed 12V charger and started charging the main drivetrain system

At this point I have both batteries charged but I cannot lock/unlock the car using either of my keyfobs. The fobs are recognised since the car can start. I can lock/unlock using the buttons inside on the door. I am also able to lock/unlock from the app.

It's just the fobs that are not working. The boot (trunk) release on the key fobs also does not work (but again fine from inside car as normal).

Have I missed some step to "re-enable" them after manually unlocking or is there something else I've missed here that's caused both of them to just stop working?

[Coastali8]

Take the key fob and hold it next to the printed key icon on the side of the steering column. Press the start button then turn off the car with the button all while holding the key fob next to the steering column. I think that will re sync the fob to the car.

If that doesn’t work take the physical key out of the key fob and use it to unlock and lock the drivers door 6 times.

I’ve never tried either one of these fixes on a BMW i8 but these are the usual fixes for re syncing a fob to the car. The i8 could be different. Good luck.

[billy.gif]

Originally Posted by guytp

Both my 12V and drivetrain batteries were dead today.

5. Charged the 12V battery for several hours until it had sufficient charge

Sorry that I cannot help with the key fob problem but the user manual says that if the 12V battery drains empty, one should connect the hybrid battery charger and when it reaches ... 10 or 20% it will automatically start charging the 12V battery.

I think that in majority of BMW plugin hybrids the hybrid battery will keep 12V battery charged as long as the hybrid battery as more than 10 or 20% charge left.

[bmwi8i8i8]

Hi did you manage to get this fixed? I have the exact same problem

[bmwi8i8i8]

I managed to get this sorted by replacing the 12v battery then recoding it using Bimmerlink, everything works perfectly now. Once the battery gets down to a certain level i think some of the electronics stop working.