Montana, Silhouette, Venture 2000-2005

Heated Oxygen Sensor

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Removal & Installation




CAUTION
Do not remove the pigtail from either the Heated Oxygen Sensor (HO2S) or the Oxygen Sensor (O2S). Removing the pigtail or the connector will affect sensor operation.


CAUTION
Handle the oxygen sensors carefully in order to prevent damage to the component. Keep the electrical connector and the exhaust inlet end free of contaminants. Do not use cleaning solvents on the sensor. Do not drop or mishandle the sensor.


NOTE
The heated oxygen sensor may be difficult to remove when engine temperature is below 120°F (48°C).


CAUTION
Excess force when removing may damage the threads in the exhaust manifold or exhaust pipe.


NOTE
A special anti-seize compound is used on the heated oxygen sensor threads. The compound consists of graphite suspended in fluid 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 an engine and if for any reason is to be reinstalled, the threads must have anti-seize compound applied before reinstallation.

3.5L Engine
Sensor 1
  1. Disconnect the HO2S Sensor 1 electrical connector.
  2.  
  3. Remove the HO2S Sensor 1 from the exhaust manifold.
  4.  
  5. Use Special Tool J-39194-B Oxygen Sensor Wrench to carefully back out the heated oxygen sensor.
  6.  

To install:

  1. Coat the threads of the HO2S sensor with anti-seize compound (GM P/N 5613695).
  2.  
  3. Install HO2S Sensor 1 and tighten to 30 ft. lbs. (41 Nm).
  4.  
  5. Connect the HO2S sensor electrical connector.
  6.  

Sensor 2


Click image to see an enlarged view

Fig. Removing HO2S 2 (Sensor 2) from exhaust pipe location on 3.5L engine

  1. Raise and safely support the vehicle.
  2.  
  3. Disconnect the HO2S Sensor 2 electrical connector.
  4.  
  5. Use Special Tool J-39194-B Oxygen Sensor Wrench to carefully back out the heated oxygen sensor.
  6.  

To install:

  1. Coat the threads of the HO2S sensor with anti-seize compound (GM P/N 5613695).
  2.  
  3. Install HO2S Sensor 2 and tighten to 30 ft. lbs. (41 Nm).
  4.  
  5. Connect the HO2S sensor electrical connector.
  6.  
  7. Lower the vehicle.
  8.  

3.9L Engine
Sensor 1
  1. Remove the intake manifold cover.
  2.  
  3. Remove the Connector Position Assurance (CPA) retainer.
  4.  
  5. Disconnect the engine harness electrical connector from the HO2S 1 connector.
  6.  
  7. Raise and safely support the vehicle.
  8.  
  9. Remove the HO2S 1 electrical connector from the ignition coil bracket.
  10.  
  11. Remove the HO2S from the exhaust manifold.
  12.  

To install:

  1. If you are re-installing the old sensor, coat the threads with anti-seize compound (GM P/N 12377953).
  2.  
  3. Install the HO2S to the exhaust manifold and tighten to 31 ft. lbs. (42 Nm).
  4.  
  5. Connect the engine harness electrical connector to the HO2S connector.
  6.  
  7. Install the CPA retainer.
  8.  
  9. Install the HO2S electrical connector to the ignition coil bracket.
  10.  
  11. Lower the vehicle.
  12.  
  13. Install the intake manifold cover.
  14.  

Sensor 2
  1. Raise and safely support the vehicle.
  2.  
  3. Remove the connector position assurance (CPA) retainer.
  4.  
  5. Disconnect the engine harness electrical connector from the HO2S 2 connector.
  6.  
  7. Remove the HO2S from the catalytic converter.
  8.  

To install:

  1. If you are re-installing the old sensor, coat the threads with anti-seize compound (GM P/N 12377953).
  2.  
  3. Install the HO2S to the catalytic converter and tighten to 31 ft. lbs. (42 Nm).
  4.  
  5. Connect the engine harness electrical connector to the HO2S connector.
  6.  
  7. Install the CPA retainer.
  8.  
  9. Lower the vehicle.
  10.  

 
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