Bricked 2014 Rex, current sensor faults preventing ready, charging, and rex operation

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dansciol

New member
Joined
Feb 17, 2025
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Hello All, my name is Dan. I run a shop in Buffalo, mostly working on hybrids and other conventional junkers. Ive owned an i3 rex for 5y, got a tow in 14 rex from a customer that won't move under its own power. Wont switch the contactors to charge, drive, or turn on rex.

Main fault codes in SME point to a current sensor issue,
21F03D HV batt unit voltage and current sensor driver fault
21f0EC HV battery current implausible
21f0ED HV voltage implausible
21F13D HV batt switch contactors turn off after fault
21F14A HV batt safety concept 2, current too low, too high or unknown

And more stored in other units as a result of this current sensor not working.
Now I am trying to find where this sensor is located. Im assuming inside the HV batt, in the safety box? or in the SME?

Ive read the I01 general electrics, and HV tech training books, but it doesn't seem to say, or show in wiring diagrams.
Does anyone know for sure?
TIA

-Dan
 
Last edited:
Thanks!, the bmw fault code site helps a lot. I didn’t see any codes listed by the guy that paid 4k for the sme and safety box.

I’m thinking change the safety box and recheck. If the sme is changed one needs the eos unit, which I don’t have. Can safety box be changed without using the eos unit?
 
I wish I could answer or help you more, but I only know what I can read about the car online. I'm a relatively new i3 owner and have been trying to learn as much as possible about them, as I cannot afford servicing at the dealer. There are others on this forum who have good knowledge of the electronics that will hopefully chime in. Best of luck!
 
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