BMW Oxygen Sensor 11787589121 0258027029 234-5054 Original Equipment Quality

BMW engine exhaust O2 sensor 11787589121 monitors exhaust oxygen content and feeds ECU to adjust AF ratio; compatible with 0258027029, 234-5054 and 55563348; fits BMW 3 Series, 5 Series, X3 with N-series engines. Installation difficulty medium; labor about 0.5-1 hour; avoid thread damage. If idle is unstable, fuel consumption rises, engine fault light on, or exhaust smell appears, sensor replacement is needed.