Kia_Sephia_Rio_Spectra_Optima_1998-2006

Heated Oxygen Sensor (HO2S)

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Location



The sensors are located in the exhaust system. On some vehicles one sensor is located up at the exhaust manifold(s) and the other sensor is located down at the catalytic converter. On other vehicles both sensors are located down at the catalytic converter.

The sensors are located in the exhaust system. On some vehicles one sensor is located up at the exhaust manifold and the other sensor is located down at the catalytic converter. On other vehicles both sensors are located down at the catalytic converter.

Testing



2000-2003

Perform a visual inspection of the sensor as follows:

  1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
  2.  
  3. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
  4.  
  5. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
  6.  
  7. Warm the engine until the coolant temperature reaches operating temperature.
  8.  
  9. Run the engine at idle speed.
  10.  
  11. Connect a voltmeter between terminal 4 (grn/brn) and ground.
  12.  
  13. Increase and decrease the engine speed quickly several times.
  14.  
  15. Specification should be 0-1.0 volt.
    NOTE
    The rear sensor voltage does not fluctuate as quickly as the front sensor.

  16.  
  17. If not as specified, inspect the on-board diagnostic system, exhaust system, intake manifold system and fuel line pressure.
  18.  
  19. If all systems are normal, replace the sensor.
  20.  
  21. To check the heater, be sure that the ignition switch is OFF.
  22.  
  23. Disconnect the sensor connector from the wire harness, if not already done.
  24.  
  25. Connect an ohmmeter between terminals 1 and 3. Measure the resistance.
  26.  
  27. Specification should be approximately 2-4 ohms at 68°F.
  28.  
  29. If not as specified, replace the sensor.
  30.  

2001-2003

Perform a visual inspection of the sensor as follows:

  1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
  2.  
  3. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
  4.  
  5. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
  6.  
  7. Warm the engine until the coolant temperature reaches 176-205°F.
  8.  
  9. Accelerate the engine to 4000 rpm. When decelerating suddenly from 4000 rpm, the voltmeter reading should be 200mV or lower.
  10.  
  11. When the engine is suddenly raced, the voltmeter reading should be 600-1000mV.
  12.  
  13. If measured value is not within specification, replace the sensor.
  14.  
  15. Turn the ignition switch to the OFF position.
  16.  
  17. Disconnect the sensor connector.
  18.  
  19. Measure the resistance between terminals 3 and 4 (component side).
  20.  
  21. On 2001 vehicles specification should be 30 ohms or more at 752°F.
  22.  
  23. On 2002 vehicles, specification should be 3.0-6.2 ohms at 68°F.
  24.  
  25. On 2003 vehicles, specification should be 3.0-6.2 ohms at 68°F. if equipped with a 2.4L engine and 4.0-5.2 ohms if equipped with a 2.7L engine.
  26.  
  27. If not, replace the sensor.
  28.  
  29. Apply battery voltage directly between terminal 3 and 4.
    NOTE
    Take care when applying the voltage. Damage will result if the terminals are incorrect or short circuited.

  30.  
  31. Connect a digital voltmeter between terminal 1 and 2.
  32.  
  33. While racing the engine, measure the sensor output voltage. Specification should be 0.6 volt (minimum) on 2.4L engine and 4.5 volts on 2.5L and 2.7L engines.
  34.  
  35. If not, replace the sensor.
  36.  

2001-2005

Perform a visual inspection of the sensor as follows:

  1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
  2.  
  3. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
  4.  
  5. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
  6.  
  7. Allow the engine to reach normal operating temperature.
  8.  
  9. Run the engine at idle speed.
  10.  
  11. Connect a voltmeter between terminal 1 (LG/R) and ground.
  12.  
  13. Increase and decrease the engine speed quickly several times.
  14.  
  15. Verify that the meter reading varies between 0-1 volt.
    NOTE
    The rear sensor voltage does not fluctuate as quickly as the front sensor.

  16.  
  17. If not a specified, inspect the on board diagnostic system, intake manifold vacuum, fuel line pressure and the exhaust system.
  18.  
  19. If all systems are normal, replace the sensor.
  20.  
  21. To inspect the sensor heater, be sure the ignition switch is OFF.
  22.  
  23. Disconnect the sensor electrical connector, if not already doe.
  24.  
  25. Connect an ohmmeter between terminals 1 and 3.
  26.  
  27. Specification should be 3-7 ohm at 68°F.
  28.  
  29. If not within specification, replace the sensor.
  30.  

2004-2006
Sensor One

Perform a visual inspection of the sensor as follows:

  1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
  2.  
  3. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
  4.  
  5. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
  6.  
  7. Turn the ignition switch to the OFF position. Disconnect the sensor connector.
  8.  
  9. Using an ohmmeter measure the resistance between terminal 5 and 6 of the sensor connector.
  10.  
  11. Specifications are as follows:

    Temperature 68°F, resistance 2.4 ohms
     
    Temperature 212°F, resistance 3.3 ohms
     
    Temperature 392°F, resistance 4.0 ohms
     
    Temperature 572°F, resistance 4.6 ohms
     
    Temperature 752°F, resistance 5.3 ohms
     
    Temperature 932°F, resistance 5.8 ohms
     
    Temperature 1112°F, resistance 6.4 ohms
     
    Temperature 1292°F, resistance 6.9 ohms
     

  12.  
  13. Replace the sensor if not within specification.
  14.  

Sensor Two

Perform a visual inspection of the sensor as follows:

  1. If the sensor tip has a black/sooty deposit, this may indicate a rich fuel mixture.
  2.  
  3. If the sensor tip has a white, gritty deposit, this may indicate an internal coolant leak.
  4.  
  5. If the sensor tip has a brown deposit, this could indicate excessive oil consumption.
  6.  
  7. Turn the ignition switch to the OFF position. Disconnect the sensor connector.
  8.  
  9. Using an ohmmeter measure the resistance between terminal 3 and 4 of the sensor connector.
  10.  
  11. Specifications are as follows:

    Temperature 68°F, resistance 9.2 ohms
     
    Temperature 212°F, resistance 10.7 ohms
     
    Temperature 392°F, resistance 13.1 ohms
     
    Temperature 572°F, resistance 14.6 ohms
     
    Temperature 752°F, resistance 17.7 ohms
     
    Temperature 932°F, resistance 19.2 ohms
     
    Temperature 1112°F, resistance 20.7 ohms
     
    Temperature 1292°F, resistance 22.5 ohms
     

  12.  
  13. Replace the sensor if not within specification.
  14.  

Operation



The exhaust gas oxygen sensor supplies the electronic control assembly with a signal which indicates either a rich or lean mixture condition, during the engine operation.

Removal & Installation



  1. Disconnect the electrical connector from the sensor.
  2.  
  3. Remove the oxygen sensor.
  4.  

To install:

  1. Installation is the reverse of the removal procedure.
    NOTE
    Apply anti-seize compound to the threaded portion of the sensor, prior to installation. Never apply anti-seize compound to the protector of the sensor.

  2.  

Operation



The exhaust gas oxygen sensor supplies the electronic control assembly with a signal which indicates either a rich or lean mixture condition, during the engine operation.

Removal & Installation



  1. Disconnect the electrical connector from the sensor.
  2.  
  3. Remove the oxygen sensor.
  4.  

To install:

  1. Installation is the reverse of the removal procedure.
    NOTE
    Apply anti-seize compound to the threaded portion of the sensor, prior to installation. Never apply anti-seize compound to the protector of the sensor.

  2.  
  3. Tighten the sensor to 22-36 ft. lbs for 2001-2005 vehicles and to 37-44 ft. lbs. for 2006 vehicles.
  4.  

Operation



The exhaust gas oxygen sensor supplies the electronic control assembly with a signal which indicates either a rich or lean mixture condition, during the engine operation.

Removal & Installation



  1. Disconnect the electrical connector from the sensor.
  2.  
  3. Remove the oxygen sensor.
  4.  

To install:

  1. Installation is the reverse of the removal procedure.
    NOTE
    Apply anti-seize compound to the threaded portion of the sensor, prior to installation. Never apply anti-seize compound to the protector of the sensor.

  2.  

 
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