GM 12592591
Oxygen Sensor

Before replacing the heated oxygen sensor (HO2S) located at position 2 it is necessary to lift the vehicle. To begin repairs disconnect the heated oxygen sensor electrical connector and remove the HO2S component through use of the Heated Oxygen Sensor Wrench (J 39194-B). When working with heated oxygen sensors it is crucial to apply anti-seize compound that includes graphite particles embedded in fluid with glass beads to the threaded areas of the sensor. This compound comes pre-applied to new or serviced sensors. The threads of the sensor need applying with anti-seize compound P/N 5613695 before performing reinstallation when using the same sensor. The heated oxygen sensor requires installation through the use of the Heated Oxygen Sensor Wrench (J 39194-B) just until it achieves 41 N.m (30 lb ft) of torque. Completing the installation requires connection of the HO2S electrical connector and a vehicle lowering.

To replace Heated Oxygen Sensor 1, one first removes connector position assurance (CPA) retainer from the heated oxygen sensor (HO2S) connection then disconnect the engine wiring harness electrical connector from the HO2S electrical connector. Next, pull off the HO2S electrical connector clip from the transmission fluid fill tube bracket. If necessary, remove the HO2S using the J 39194-B Heated Oxygen Sensor Wrench (J 39194-B). During the installation, clean the threads of the old sensor in case it is going to be reused and apply anti-seize compound (P/N 12377953), which is actually composed of liquid graphite and glass beads that make removal easier. Mount the HO2S according to the J 39194-B (J 39194-B) and tighten it to 42 N.m (31 lb ft). Reconnect the engine wiring harness electrical connector to the HO2S electrical connector, connect the HO2S electrical connector clip to the transmission fluid fill tube bracket, and lastly, the CPA retainer is fitted to the HO2S connection.

Yes, new service sensors come with this compound pre-applied.

It consists of graphite suspended in fluid and glass beads, which facilitates easier removal in the future.

Rotate the sensor several turns counterclockwise before threading it into the catalytic converter.

Use the Heated Oxygen Sensor Wrench (J 39194-B), if required.

Disconnect the HO2S electrical connector from the engine wiring harness.

Remove the connector position assurance (CPA) retainer from the HO2S connection and disconnect the engine wiring harness electrical connector from the HO2S electrical connector.

Reconnect the HO2S electrical connector.