Read the whole fault set
The source discusses intermittent power loss with faults including 120308 and companion air-mass, Valvetronic or tank-ventilation faults. Connections and charge-air leaks are checked before deciding that software is the explanation.
Sources 1
Before replacing anything
Preserve the evidence
Save all codes, not just the one shown by an app’s headline. Record whether the warning followed acceleration, a restart or recent work. Note whether power returned after restarting without using that as proof of a fix.
List modifications honestly
Give the workshop the current intake, charge-air and software configuration, if known. Do not assume the previous owner left the car stock. Supply invoices or part identification rather than guesses.
Hardware and software are different outcomes
Ask which physical checks were performed and whether the diagnostic plan found a fault. The bulletin’s software correction is conditional; it is not permission to skip leak or component diagnosis.
Sources 1
Choose parts after the finding
Keep the inspection result and current software identification with the repair record. Use the exact engine and production date when a confirmed fault requires a part.
Sources / references 1
- BMW — SI B12 36 15, April 2016 ↗Reviewed Sep 27, 2026
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