The Service Engine Light Came On Two Days Ago. Yesterday I Went To Auto Zone And Borrowed The Obd 2 Code Reader. It Came Up With Code P0161 . "02 Sensor Heater Circuit Malfunction" I Drove My Truck All Day And To This Point The Code Has Not Returned. Should I Not Worry About It. Also Truck Is A Tahoe 1997 4x4 And Is Running Well. Any Tips Or Ideas Are Appreciated.

P0161 O2 Sensor Heater Circuit Malfunction Bank 2 Sensor 2 (This means passenger side, O2 sensor located after the Catylitic Converter)


Your mileage will point you in the right direction. I got over 130,000 miles on my factory original O2's . Technically, they should be replaced every 100,000 according to GM. Shop around though, going rate for Downstream Sensors (After Cat) is $70ea, whereas for UpStream sensors is only $50ea. Hope this helps -Chris

Thank You For Your Help. It Definately Points Me The Right Direction. My Car Is Approaching 126,000 Miles. I Hope This Sensor Is Eassy To Replace. Now How Would I Dertermine Wether I Need An Upstream Or A Down Stream Sensor.