One supplier's dirty brake line recalled 1.5 million BMWs.

In 2024 BMW launched the largest recall in its history: roughly 1.5 million cars worldwide, built between June 2022 and August 2024, across the 5 Series, 7 Series, several crossovers, two MINI variants and the Rolls-Royce Spectre. The cause was not scattered across the supply chain. It was one part — the Integrated Brake System (IBS) — made by a single supplier, Continental, that combines actuation, brake control and power assistance into one module.

The defect was mundane and industrial. According to reporting on Continental's own production, workers on the brake circuit-board line failed to keep it clean enough, leaving contamination that could stop the module meeting spec. The safety consequence was serious: a reduction or loss of power-assist braking, meaning far harder pedal effort and a higher risk of a crash. By the time the recall landed, BMW had logged around 459 warranty claims that related, or might relate, to the fault.

The cost ran beyond parts and labour. BMW put the warranty bill in the high three-digit-million range and cut its 2024 operating-margin guidance from 8–10 percent down to 6–7 percent, while trimming its delivery outlook from a slight increase to a slight decrease. China, where about 370,000 of the cars sat, was the worst-hit single market; the United States had roughly 270,000 and Germany about 150,000.

The decision error was concentration without containment. BMW had folded a safety-critical function into one integrated module from one supplier and let it run across an entire generation of vehicles for two years before the pattern was caught. Single-sourcing a part is defensible; single-sourcing a part whose failure mode is the whole braking system, and noticing only through warranty claims, is the mistake. Continental said the car's own sensors should warn a driver well before the failure — but the recall still covered 1.5 million cars.