Hyundai Coupes/Sedans 1994-1998 Repair Guide

Oxygen Sensor (O2)

Print

OPERATION



The oxygen sensor is mounted either in the exhaust manifold or the exhaust pipe. Some vehicles use two oxygen sensors. The output signal from the sensor, which varies with the oxygen content of the exhaust gas stream, is sent to the ECM for use in controlling closed loop fuel delivery. The oxygen sensor must at a certain temperature to function properly. Some sensors contain an internal heater to boost sensor temperature during cold starts.

TESTING



See Figures 1, 2 and 3



Click image to see an enlarged view

Fig. Fig. 1: Oxygen sensor schematic-except 1.5L (VIN E) engine



Click image to see an enlarged view

Fig. Fig. 2: Oxygen sensor schematic-1.5L (VIN E) engine



Click image to see an enlarged view

Fig. Fig. 3: Oxygen sensor heater terminal identification-1.5L (VIN E) engine

  1. Start the engine and allow it to reach operating temperature.
  2.  
  3. Disconnect the oxygen sensor connector.
  4.  
  5. Measure resistance between the sensor signal and ground terminals
    1. With the engine idling, voltage should be 400 millivolts or less.
    2.  
    3. When the engine is suddenly accelerated, voltage should be 600-1000 millivolts.
    4.  
    5. When the engine is suddenly decelerated from 4000 rpm, voltage should be 200 millivolts or less.
    6.  

  6.  
  7. If sensor is equipped with a heater (3 or 4 terminal connector), measure resistance between the heater positive and negative terminals.
    1. With the heater at 750°F (400°C), resistance should be 30 ohms or more.
    2.  

  8.  
  9. If voltage or resistance is not within specification, sensor is faulty.
  10.  
  11. If voltage and resistance are within specifications, check power and ground circuits.
  12.  

REMOVAL & INSTALLATION



See Figures 4 through 11



Click image to see an enlarged view

Fig. Fig. 4: Disconnect the oxygen sensor connector....



Click image to see an enlarged view

Fig. Fig. 5: ....remove the exhaust manifold shield bolts....



Click image to see an enlarged view

Fig. Fig. 6: ....and shield....



Click image to see an enlarged view

Fig. Fig. 7: to gain access to the oxygen sensor



Click image to see an enlarged view

Fig. Fig. 8: Spray the oxygen sensor with penetrating lubricant....



Click image to see an enlarged view

Fig. Fig. 9: ....and using the proper wrench....



Click image to see an enlarged view

Fig. Fig. 10: ....carefully loosen the sensor....



Click image to see an enlarged view

Fig. Fig. 11: ....then remove it from the exhaust manifold

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the exhaust heat shield as necessary to gain access to the sensor.
  4.  
  5. Label and disconnect the sensor electrical harness
  6.  

Special oxygen sensor wrenches are available from local tool suppliers.

  1. Carefully remove the sensor using an appropriate wrench.
  2.  

To Install:
  1. Lubricate the sensor threads with antiseize compound.
  2.  

Take care to allow the antiseize to contact only the sensor threads.

  1. Carefully install the sensor and tighten to 29-36 ft. lbs. (40-50 Nm) on all engines except 1.5 (VIN K), 1.8L (VIN M) and 2.0L (VIN F). Tighten 1.5 (VIN K), 1.8L (VIN M) and 2.0L (VIN F) sensors to 37-44 ft. lbs. (50-60 Nm).
  2.  
  3. Connect the sensor electrical harness
  4.  
  5. Install trim panels or components previously removed to gain access to the ECM.
  6.  
  7. Connect the negative battery cable.
  8.  

 
label.common.footer.alt.autozoneLogo