Fault when switching the car to on

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New member
Dec 29, 2021
Hi Guys,

I have a i3 Rex from 2015 with approx. 50.000 km.
In April this year I got the first time the yellow message when turning on the car which says in other words that the REX is not available. Switching off the car and back on the faul is gone. Since approx. 1 month I get the message more often and I noticed that it is more likely when the car has been charged before...

I read out the fault codes with ISTA and the faults seem a little bit strange for me (please note that I translated the faults into english, so the real words might be a little bit different):

1. 21DD03 REX Generator Rotor Position Sensor signal implausible. (50651 km)
2. 22283A Charge Management, loading aim cannot be reached. (50381 km)
3. 222862 Info emergency run manager: Something about active shortage (not further specified). (50569 km)
4. 222866 Info emergency run manager: problem with the rotor position sensor. (50386 km)
5. 222868 Info emergency run manager: fault comes on when the REME has a power converter temperature fault. (50386 km)
6. 222855 Check Control Message ID848: Overtemperatur electric machine (50386 km)
7. 2228DB Check Control Message (ID 900): low range (50381 km)

According to ISTA there should be further faults (more detailed) for the codes 222862 and 222868. But there are no more faults...

My car needs also the charging electronic replaced (BMW recall), but this is about corrosion of the charger housing resulting in coolant leakages. So I do not thinkt that it is related to the faults above.

Has anyone an idea what is going wrong with my car?

Thank you!

Best regards,

Very low 12 V system voltage, even briefly, can result in multiple unrelated diagnostic trouble codes (DTC's) being set. A weak 12 V battery could cause such symptoms.