BMW 5 Series Front Oxygen Sensor 11787589139 0258017231 OEM Replacement Fuel Economy Improvement

When a BMW 5 Series experiences idle instability, weak acceleration, or noticeably higher fuel consumption, and the engine check light shows codes such as P0171 or P0174, the front oxygen sensor may be aging or failed. When functioning, it monitors exhaust oxygen content in real time and feeds signals to the ECU to precisely adjust the air-fuel ratio, ensuring complete combustion, better fuel economy, and lower emissions. This is an OEM replacement; OEM number 11787589139; compatible with 0258017231; fits BMW 5 Series (F10/F11/F18 chassis; N20/N55 engines). Use a dedicated socket; avoid excessive force to protect threads; clean exhaust interface and apply anti-seize; keep sensor wiring away from high-temperature parts.