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.

 

[The-Traveler]

I’ve done that stuff before but a lot of the messing about I did with two batteries and a charger while forgetting to disconnect HV switch so I think I messed up the HV module(s)

Anyway it’s plugged in now and the only good news I see is that it’s drawing 50w -60w or so from the charging plug.

 

[3rigel]

Maybe good news. Does it drive? Is the HV battery already full so not needing to charge?

 

[The-Traveler]

Maybe good news. Does it drive? Is the HV battery already full so not needing to charge?

Nope I can’t get the power button to go blue, it says drive train error, hybrid battery errors, and many other errors. Fans spin at 100% when on accessory mode. HV battery was full a week or two ago prior to the 12v dying

 

[3rigel]

Oh dear, I have an EME issue and that's the symptom I get too as it drops into a fail safe mode. All the best, let us know what solves it.

 

[The-Traveler]

Oh dear, I have an EME issue and that's the symptom I get too as it drops into a fail safe mode. All the best, let us know what solves it.

Yeah EME was red in ista when this first started, it has since come back yellow but I can’t call up ecu functions the button is grayed out and I can’t clear errors with ista it does the left side of the module tree, they all go green from gray, then it does a changeover, all modules on the right stay yellow and after trying to clear it says voltage below 12.55v in ista. But my battery tender was saying it was 13.2 so I don’t know. I’m pretty discouraged and nervous to flash these modules with esys. Wish someone else had this exact problem. If you see later in my video, the errors messages are very worrisome.

 

[3rigel]

I'm not that familiar with ista at the moment but would suspect if ista needs to see a certain voltage and it's not seeing it or doesn't think it's seeing it and is acting accordingly I guess. Have you got a DVM to see which one is telling the truth?

 

[The-Traveler]

I only have a multimeter

 

[alohart]

I only have a multimeter

That should work. However, you need to check the resting voltage of your 12V battery, not the output of the DC-DC converter. To do that, pop the frunk before you go to bed (no need to open it completely). Then the next morning, open the frunk without unlocking or opening the doors or hatch to prevent the HV system and probably DC-DC converter from turning on. Then measure the voltage between the 12V battery's terminals which would be its resting voltage. The negative cable clamp is easy to reach but the positive cable clamp is encased in a red plastic cover. You should be able to probe around with your multimeter lead from the direction of the center of the battery until the meter displays a real voltage (i.e., in the 12.0-12.7V range).