GM Service Manual Online
For 1990-2009 cars only

Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 NT3

Removal Procedure

    Caution: Refer to Safety Glasses Caution in the Preface section.

    Caution: Refer to Vehicle Lifting Caution in the Preface section.

  1. Ignition OFF.

  2. Object Number: 1949871  Size: SH
  3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  4. Disconnect the heated oxygen sensor (HO2S) from the electrical connector retaining clip (1).
  5. Disconnect the heated oxygen sensor (HO2S) electrical connector (2) from the harness connector on the transmission case.
  6. Remove the catalytic converter. refer to Catalytic Converter Replacement - Right Side.
  7. Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.


    Object Number: 1949875  Size: SH
  8. Remove the HO2S (1) from the catalytic converter.

Installation Procedure

    Notice: Refer to Component Fastener Tightening Notice in the Preface section.


    Object Number: 1949875  Size: SH

    Important: New oxygen sensors should have a special anti-seize compound already applied to the sensor threads. If you are installing the original sensor, apply an approved anti-seize compound to the sensor threads.

  1. Install the HO2S to the catalytic converter.
  2. Tighten
    Tighten the HO2S to 40 N·m (30 lb ft).

  3. Install the catalytic converter to the vehicle. Refer to Catalytic Converter Replacement - Right Side.

  4. Object Number: 1949871  Size: SH
  5. Connect the heated oxygen sensor (HO2S) electrical connector (2) to the harness connector on the transmission case.
  6. Connect the heated oxygen sensor (HO2S) to the electrical connector retaining clip (1).
  7. Lower the vehicle.

Heated Oxygen Sensor Replacement - Bank 1 Sensor 1 NT4

Removal Procedure

  1. Ignition OFF.
  2. Caution: Refer to Battery Disconnect Warning in the Preface section.

  3. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .
  4. Remove the engine cover. Refer to Engine Cover Replacement .

  5. Object Number: 2173129  Size: SH
  6. Disconnect the heated oxygen sensor (HO2S) electrical connector (1).
  7. Notice: Refer to Heated Oxygen and Oxygen Sensor Notice in the Preface section.

  8. Remove the HO2S (2) from the exhaust manifold.

Installation Procedure

    Notice: Refer to Component Fastener Tightening Notice in the Preface section.


    Object Number: 2173129  Size: SH

    Important: New oxygen sensors should have a special anti-seize compound already applied to the sensor threads. If you are installing the original sensor, apply an approved anti-seize compound to the sensor threads.

  1. Install the HO2S (2) into the exhaust manifold.
  2. Tighten
    Tighten the HO2S to 40 N·m (30 lb ft).

  3. Connect the HO2S electrical connector (1).
  4. Install the engine cover. Refer to Engine Cover Replacement.
  5. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection .