Mazda6 Rear Oxygen Sensor LFH2-18-861 Universal Brand Sensitive Detection

When Mazda6 shows idle instability, higher fuel consumption, or engine fault codes (P0136/P0141, etc.), the downstream oxygen sensor is aging or failed and cannot monitor exhaust oxygen accurately. It feeds back to the ECU after the catalytic converter to adjust the air-fuel ratio for emissions compliance and fuel economy. OEM LFH2-18-861; fits Mazda6 (2002-2015) and related platforms. Before installation, disconnect the battery negative and ensure sensor threads are clean of carbon buildup; torque with a dedicated socket per specification to avoid ceramic damage.