G6 2005-2007

Heated Oxygen Sensor

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Operation



The fuel control Heated Oxygen Sensors (Bank 1 HO2S 1 and Bank 2 HO2S 1) are mounted in the exhaust manifolds where they can monitor the oxygen content of the exhaust gas stream. The oxygen present in the exhaust gas reacts with the sensor to produce a voltage output. This voltage should constantly fluctuate from approximately 100mV (high oxygen content - lean mixture) to 900mV (low oxygen content - rich mixture). The heated oxygen sensor voltage can be monitored with a scan tool. By monitoring the voltage output of the oxygen sensor, the ECM can calculate what fuel mixture command to send the injectors (lean mixture-low HO2S voltage = rich command, rich mixture-high HO2S voltage = lean command).

Removal & Installation



2.4L Engine

NOTE
The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor. The use of excessive force may damage the threads in the exhaust manifold/pipe.


WARNING
The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F).

  1. Raise and support the vehicle.
  2.  
  3. Remove the Connector Position Assurance (CPA) retainer.
  4.  
  5. Disconnect the HO2S electrical connector.
  6.  
  7. For the front sensor remove the HO2S electrical connector clip from the thermostat housing.
  8.  
  9. Using the J 39194 or equivalent, remove the HO2S.
  10.  

To Install:


NOTE
A special anti-seize compound is used on the HO2S threads. The 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 already have the compound applied to the threads. If the sensor is removed and is to be reinstalled, the threads must be coated with an anti-seize compound before reinstallation.

  1. If reinstalling the old HO2S, coat the threads with anti-seize compound.
  2.  
  3. Using the J 39194 or equivalent, install the HO2S.
  4.  
  5. Tighten the HO2S to 30 ft. lbs. (41 Nm).
  6.  
  7. Connect the HO2S electrical connector.
  8.  
  9. For the front sensor install the HO2S electrical connector clip to the thermostat housing.
  10.  
  11. Install the CPA retainer.
  12.  
  13. Lower the vehicle.
  14.  

When replacing the HO2S perform the following:



A code clear with a scan tool, regardless of whether or not a DTC is set
 
HO2S heater resistance learn reset with a scan tool, where available
 

Perform the above in order to reset the HO2S resistance learned value and avoid possible HO2S failure.

3.5L, 3.6L And 3.9L Engine

NOTE
The oxygen sensor uses a permanently attached pigtail and connector. Do not remove the pigtail from the oxygen sensor. Damage to or removal of the pigtail connector could affect proper operation of the oxygen sensor. The use of excessive force may damage the threads in the exhaust manifold/pipe.


WARNING
The HO2S may be difficult to remove when the engine temperature is less than 48°C (120°F).

  1. Raise and support the vehicle.
  2.  
  3. Remove the Connector Position Assurance (CPA) retainer.
  4.  
  5. Disconnect the HO2S electrical connector.
  6.  
  7. Using the J 39194 or equivalent, remove the HO2S.
  8.  

To Install:


NOTE
A special anti-seize compound is used on the HO2S threads. The 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 already have the compound applied to the threads. If the sensor is removed and is to be reinstalled, the threads must be coated with an anti-seize compound before reinstallation.

  1. If reinstalling the old HO2S, coat the threads with anti-seize compound.
  2.  
  3. Using the J 39194 or equivalent, install the HO2S.
  4.  
  5. Tighten the HO2S to 31 ft. lbs. (42 Nm).
  6.  
  7. Connect the HO2S electrical connector.
  8.  
  9. Install the CPA retainer.
  10.  
  11. Lower the vehicle.
  12.  

When replacing the HO2S perform the following:



A code clear with a scan tool, regardless of whether or not a DTC is set
 
HO2S heater resistance learn reset with a scan tool, where available
 

Perform the above in order to reset the HO2S resistance learned value and avoid possible HO2S failure.

Testing





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Fig. Front heated Oxygen Sensor (H02S) 2.4L engine electrical connector (Sensor 1)



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Fig. Rear heated oxygen sensor (H02S) 2.4L engine electrical connector (Sensor 2)



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Fig. Front heated Oxygen Sensor (H02S) All V6 engines electrical connector (Bank 1 Sensor 1)



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Fig. Rear heated oxygen sensor (H02S) V6 All engines electrical connector (Bank 1 Sensor 2)



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Fig. Front heated Oxygen Sensor (H02S) V6 All engines electrical connector (Bank 2 Sensor 1)



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Fig. Rear heated oxygen sensor (H02S) V6 All engines electrical connector (Bank 2 Sensor 2)

  1. Ignition OFF, disconnect the scan tool and wait 60 seconds to ensure all modules are powered down.
  2.  
  3. Ignition OFF, disconnect the harness connector at the appropriate HO2S.
  4.  
  5. Ignition OFF, measure for less than 5 ohms resistance between the appropriate HO2S low signal circuit terminal A and ground.
    1. If more than the specified range, test the appropriate HO2S low signal circuit for an open/high resistance. If the circuit tests normal, replace the ECM.
    2.  

  6.  
  7. Ignition ON, verify the appropriate scan tool HO2S parameter is approximately 450 mV.
    1. If more than the specified value, test the appropriate HO2S high signal circuit for a short to voltage. If the circuit tests normal, replace the ECM.
    2.  
    3. If less than the specified value, test the appropriate HO2S high signal circuit for a short to ground. If the circuit tests normal, replace the ECM.
    4.  

  8.  
  9. Ignition ON, install a 3A fused jumper wire at the HO2S high signal circuit terminal B. Toggle the jumper wire between the HO2S low signal circuit terminal A and battery voltage. Verify the appropriate scan tool HO2S parameter toggles between 0 mV and approximately 1,000 mV
    1. If the appropriate scan tool HO2S parameter does not toggle correctly, test the HO2S high signal circuit for an open/high resistance. If the circuits test normal, replace the ECM.
    2.  

  10.  
  11. If all circuits test normal, replace the appropriate HO2S.
  12.  

 
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