Toyota Downstream Rear Oxygen Sensor 89465-80011/234-4154 Catalytic Converter Monitor

When your Toyota dashboard shows engine fault lights (e.g., P0138 or P0141), or symptoms of abnormal fuel consumption, acceleration loss, or pungent exhaust odors, usually the downstream rear oxygen sensor (catalytic converter monitoring) has aged or failed. This sensor monitors catalytic converter efficiency in real time and feeds back to ECU to adjust air-fuel ratio, ensuring engine performance stability. This product's OEM numbers are 89465-80011/234-4154 and fits multiple models (e.g., Camry, Corolla, RAV4, Highlander), with interchangeable parts numbers including 8946509040, 8946509110, etc. During installation, use a professional socket wrench to avoid damaging threads, and keep the sensor harness and exhaust pipe at appropriate distance to prevent heat damage.