BMW i3 2014–2021 — technical service bulletin
Bulletin B120920 · NHTSA communication 10181216 · issued Sep 1, 2020
Technical service bulletin
communication type
Engine and Engine Cooling
component
2014–2021
model years
9
vehicle entries
Official summary
I01 REX MISFIRES AT HIGH ALTITUDES USING WINTER-BLEND FUEL: The check engine light (MIL) is displayed, and in some cases the range extender (REx) engine will run rough for about 1 to 2 seconds during cold start.
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.