2015 BEV - Weird Malfunction - Brake & Charging Warnings

[slcab125]

This morning I started my 2015 i3 and received two warnings. The first was a "Braking System" "continue to Drive moderately." Then a second warning stated that the charging system was malfunctioning and my car did not charge, however, the car fully charged overnight and my battery was fully charged, finally a loud fan came on (the fan sound was similar to when charging the car in high heat). When pressing on the brake, there was a lot of resistance and it was hard to press. I shut off my car and check the brake fluid, and there is plenty of brake fluid. I turned off my car and decided to do a search for posts about these errors. Right before deciding to write this post I went out to my car to take a photo of the errors and when I turned on my car it was completely back to normal!!! I drove it around my block carefully and the car is working perfectly. Does anyone have ANY idea what could be going wrong? Help Please!

 

[websterize]

How old is your 12V battery? Might need to renew it.

 

[slcab125]

Hi There - That is a great question, 12 Volt battery was replaced one year ago. When the 12 volt died the car became a "brick." I am thinking of taking the car to get scanned to see what codes pop up before heading over to the dealership. The thought of the dealership and the per hour costs drives me nuts!

 

[frictioncircle]

Might your your one-year old 12V AUX have been less than fully charged at the time of installation (this is common occurrence)?

My thought is that if you installed a partially-charged new 12V AUX battery and didn't drive very many miles since 2021, your AUX battery may be in a state of discharge despite being relatively new.

Before going to the dealer, you could remove the 12V battery, recharge it with a good charger, and reinstall it.

After reinstallation it'd be a good idea to register the new battery:

https://www.mybmwi3.com/forum/viewtopic.php?t=17706

 

[3pete]

I am thinking of taking the car to get scanned to see what codes pop up before heading over to the dealership. The thought of the dealership and the per hour costs drives me nuts!

The Bimmerlink app and a corresponding OBDII adapter can do the code scan as well. That could be a reasonable investment to avoid unnecessary dealership visits.