Hyundai Sonata Rear Oxygen Sensor 39210-25110, stable exhaust gas monitoring

When your Hyundai Yuedong Sonata or another Hyundai model shows engine fault light, significantly higher fuel consumption, unstable idle or weak acceleration, the rear oxygen sensor is likely aging and failing, failing to monitor exhaust oxygen content accurately. The sensor normally feeds ECU with residual oxygen concentration to help control air-fuel ratio precisely, ensuring combustion efficiency and emission compliance. Compatible with Hyundai Yuedong/Sonata models; OEM 39210-25110. When installing, ensure sensor threads are clean, use dedicated socket to tighten to specified torque, avoid ceramic damage, and verify wiring connector is firmly attached.