Mercedes-Benz Oxygen Sensor A0025400117 (0258006473), Original Quality Replacement.

This Mercedes oxygen sensor (A0025400117 / 0258006473) is designed for 3.0L–5.5L engines in the 2005–2013 C-Class (W204), E-Class (W212), S-Class (W221), and ML-Class (W164) with M272 or M273 engines. As the upstream O2 sensor, it monitors oxygen content in exhaust and feeds back to the ECU to precisely control air-fuel ratio, ensuring combustion efficiency and emissions compliance. OEM number A0025400117 (cross-checkable with Bosch 0258006473) for direct compatibility. Replacement difficulty medium; use a dedicated socket for removal; avoid pulling the wiring harness; clean threads and apply anti-seize agent before installation; after installation, clear fault codes with a diagnostic tool. This sensor is an OEM-quality replacement compatible with Mercedes original systems, helping reduce fuel consumption and extend the catalytic converter life; suitable for bulk stock for maintenance.