GM Service Manual Online
For 1990-2009 cars only

Special Tools

EN-48259 Oxygen Sensor Remover/Installer

Removal Procedure

    Warning: Refer to Battery Disconnect Warning in the Preface section.

    Caution: Refer to Heated Oxygen and Oxygen Sensor Caution in the Preface section.


    Object Number: 2178817  Size: SH
  1. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Disconnect the HO2S1 connector.
  3. Install the EN-48259 .
  4. Remove the HO2S1 (1).

Installation Procedure


    Object Number: 2178817  Size: SH

    Note: A special anti-seize compound is used on the oxygen sensor threads. This compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from any engine and if for any reason it is to be reinstalled, the threads must have anti seize compound applied before reinstallation.

  1. Coat the threads of the HO2S1 with an anti-seize compound, if needed.
  2. Caution: Refer to Fastener Caution in the Preface section.

    Note: Ensure the HO2S1 sensor heat shield (2) is installed with the slot facing away from the exhaust manifold.

  3. Install the HO2S1 (1) into the exhaust manifold.
  4. Tighten
    Tighten the HO2S1 to 40 N·m (29.5 lb ft).

  5. Connect the battery negative cable. Refer to Battery Negative Cable Disconnection and Connection.