Slight jolt at idle after 30–50 s stationary with Start/Stop off (B58 mild hybrid): it is normal

Engine / equipment

BMW 3.0 petrol B58 48 V mild hybrid (B58B30M2)

Period mentioned

2024 (US model years)

Symptoms

With Start/Stop off and the car stationary, after about 30–50 seconds at idle there is a slight jolt or change in engine speed that feels like a misfire; no warning light and no fault codes.

Possible cause described

It is not a fault: while stationary, the engine is turned only by the crankshaft starter-generator, without combustion, until the 48 V battery drops to a certain charge; then combustion resumes with a slight jolt. BMW explains it in bulletin SIB 12 11 26.

Check for the garage

If there are no codes or warning lights, tell the garage BMW considers it normal operation (SIB 12 11 26) to avoid replacing coils, spark plugs or injectors.

Cost cited in the source

No verified estimate; ask the garage for a quote.A rough figure from the original database, not an up-to-date quote.

Sources from the original database