GM 19178958
Oxygen Sensor

The first step for HO2S (HO2S1) replacement involves disconnecting its electrical connector. Users must apply a special anti-seize compound to heated oxygen sensor threads because this solution includes graphite dispersed in fluid together with glass beads. The sensor's removal process becomes simpler because the glass beads remain behind as the graphite material burns off. The new or service sensors arrive with this substance already in place. When reinstalling sensors always put back anti-seize compound on their threads before installing. The Heated Oxygen Sensor Socket (J 39194-B) should be used to safely reverse out the heated oxygen sensor. Before sensor installation apply anti-seize compound P/N 5613695 or equivalent to heated oxygen sensor/catalyst monitor threads when needed. The installation procedure includes fitting the Heated Oxygen Sensor while applying 42 ± 4 Nm (31 lb ft) torque to the HO2S 1 (Pre-catalytic converter). Finally, reconnect the electrical connector.

A permanently attached pigtail and connector on the Heated Oxygen Sensor (HO2S) and Oxygen Sensor protects proper sensor function when kept undisturbed. Users must handle these sensors carefully with close attention to the in-line electrical connector and louvered end that requires protection from grease and dirt and cleanup agent avoidance. The first step to remove a heated oxygen sensor is turning OFF the ignition system followed by lifting the vehicle when changing HO2S 2 or you can remove the fuel injector sight shield when changing HO2S 1. The sensor electrical connector should be disconnected before carefully removing the heated oxygen sensor. When installing the heated oxygen sensor first apply anti-seize compound P/N 5613695 to its threaded section unless needed then securely tighten the sensor to 41 N.m (30 lb ft). Reinstall the HO2S sensor electrical connector and proceed with lowering the vehicle when working on HO2S 2 or with replacing the fuel injector sight shield when working on HO2S 1.

When installing a replacement Heated Oxygen Sensor (HO2S1) handle it gently but ensure both the electrical connector and louvered end remain free of grease and dirt contaminants because cleaning solutions must not be used. It is important to avoid repairing wiring problems with connectors or terminals; simply replace the affected components when any damage occurs. The oxygen sensor requires complete replacement when either sensor components or other vital wiring deteriorates. The heated oxygen sensor's pigtail along with its harness wires must stay uncovered and without kinks because exposure allows foreign materials to enter and reduce performance. Every oxygen sensor requires a working ground wire connection and no peripheral vehicle harness seal can be removed to ensure proper water prevention. Use Packard's Crimp and Splice Seals Terminal Repair Kit for necessary repairs since soldering methods should be avoided to stop air reference blockages. Before removing the heated oxygen sensor maintain an engine temperature of 120°F (48°C) and above to protect exhaust manifold and pipe thread integrity. Begin the installation process by shutting down the ignition system then disconnecting the sensor's power connection. Users must apply GM P/N 5613695 special anti-seize compound to threads of heated oxygen sensor/catalyst monitor unless previously provided with an applied anti-seize compound from new or serviced sensors. The J 39194-B heated oxygen sensor wrench helps you disassemble the sensor in proper manner. The procedure calls for tightening the HO2S 1 (pre-catalytic converter) to 42 ± 4 N.m (31 lb ft) following sensor electrical connector reattachment.

Carefully remove the rear oxygen sensor from the rear exhaust manifold using the Oxygen Sensor Wrench (J 39194).

Reused sensors should be coated with anti-seize compound P/N 5613695 or equivalent.

Take off the HO2S retaining clip from the bracket.

The splash shield and the HO2S electrical connector retaining tab.

The tools required include the Oxygen Sensor Wrench (J 39194).

Ensure the engine temperature is above 48°C (120°F) to facilitate removal.

Use the Oxygen Sensor Wrench (J 39194) to remove the oxygen sensor from the exhaust pipe.

Lower the vehicle, connect the electrical connector to the HO2S, attach the electrical connector tab to the bracket, install the electrical connector retainer, and finally reinstall the fuel injection sight shield.

Remove the HO2S retaining clip from the bracket, disconnect the HO2S electrical connector tab from the retaining clip, and remove the electrical connector retainer.

Begin by removing the fuel injector sight shield.

Raise and support the vehicle, then carefully remove the rear oxygen sensor from the rear exhaust manifold using the Oxygen Sensor Wrench (J 39194).

Begin by raising and supporting the vehicle.

The rear oxygen sensor should be tightened to 41 N.m (30 lb ft).

Begin by turning the ignition OFF.

Handle them carefully, ensuring the in-line electrical connector and the louvered end remain free of grease, dirt, or contaminants, and avoid using any cleaning solvents.

Remove the HO2S electrical CPA retainer and disconnect the HO2S wiring harness connector from the HO2S electrical connector.

Anti-seize compound P/N 5613695, or an equivalent.

It facilitates easier removal of the sensor in the future.

It facilitates easier removal of the sensor in the future.

Hand start the heated oxygen sensor and tighten it to 42 N.m (31 lb ft).

Begin by raising and supporting the vehicle.

Ensure that anti-seize compound (P/N 5613695) is applied to the threads before reinstallation.

The Heated Oxygen Sensor Socket (J 39194-B).

Use the heated oxygen sensor wrench (J 39194).

Coat the threads with anti-seize compound P/N 5613695 or an equivalent if necessary.

Anti-seize compound must be reapplied to the threads.

Carefully back out the HO2S 2 using the Heated Oxygen Sensor Wrench (J 39794-8).

Install the HO2S 1 and use the Heated Oxygen Sensor Wrench (J 39194-B) to tighten it to 41 N.m (30 lb ft).

Coat the threads with anti-seize compound GM P/N 25613695 or an equivalent if necessary.

First raise and support the vehicle.

Connect the sensor electrical connector and lower the vehicle.