BMW i4 2021–2024 — technical service bulletin
Bulletin B120523 · NHTSA communication 10250361 · issued Feb 6, 2024
Technical service bulletin
communication type
Power Train
component
2021–2024
model years
10
vehicle entries
Official summary
The customer states there is a Drivetrain Malfunction message displayed in the instrument cluster. In addition, the following fault memory entries are saved in the CCU (Combined Charging Unit) 0317F2 - High-voltage system, insulation fault detected: when switch contactors are closed. 0317F1 - High-voltage system, insulation resistance below warning threshold: when switch contactors are closed. The fault memory entries (isolation faults) can occur both individually and in combination and must be traced back to the eDrive motor based on the ISTA test procedure. If ISTA test procedure lists possi
Vehicles covered
What a TSB means. Technical service bulletins are repair guidance manufacturers send to dealers — they are not recalls, and repairs are not automatically free (warranty extensions are an exception worth checking). The full document is available via NHTSA’s vehicle lookup.