BMW M4 2015–2018 — technical service bulletin
Bulletin B122216 · NHTSA communication 10135027 · issued Feb 1, 2018
Technical service bulletin
communication type
Engine
component
2015–2018
model years
4
vehicle entries
Official summary
WATER INJECTION SYSTEM WATER LEVEL TOO LOW: Check Control (CC) Message Water level too low, engine performance only available to a limited degree is displayed.
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.