Replacement The Downstream Oxygen Sensor Unit

Information 

• If there is no fault in the Downstream oxygen sensor circuit, it is possible to suspect that the rear oxygen sensor is defective.

  In this case, check if the fault code has been cleared by replacing the Downstream oxygen sensor.

• If the failure continues even after replacing the Downstream oxygen sensor, do not replace it as it is not the cause of the failure.

1. Turn OFF the IGN switch and separate the battery (-) terminal.
2. Refer to the "appropriate service information" to disconnect the Downstream oxygen sensor.
3. Refer to the "appropriate service information" to install the Downstream oxygen sensor in the reverse order of removal.

   Information 

   When exchanging the oxygen sensor, be sure to perform inspection for "Resetting Adaptive Values" procedure.

   CAUTION:

   • Install the unit with the specified torques.
   • If the unit is dropped, there may be invisible damages. Check the performance before use.
   CAUTION:

   • Oil ingredients of cleaners, sprays or greases could degrade the performance of the lambda sensor. Do not use them on the sensing part and connector of the sensor.
   • Ensure that the sensor wiring does not touch exhaust systems, such as an exhaust manifold, otherwise, it could get damaged.
   CAUTION:

   • When replacing a single oxygen sensor unit, the "Resetting Adaptive Values" procedure must be performed. Otherwise, vehicle performance and related problems may occur from the time of parts replacement to the completion of automatic learning.
   • If the unit is dropped, there may be invisible damages. Check the performance before use.
4. IGN Switch "OFF".
5. Connect the GDS to the DLC.
6. IGN Switch "ON".
7. Using GDS, be sure to perform inspection for "Resetting Adaptive Values" in "Vehicle S/W Management" procedure.

   Courtesy of HYUNDAI MOTOR AMERICA

8. Check that the fault code does not reoccur and that it operates normally.

   OK 

   Since the system is operating normally, it is judged to be a failure of the Downstream oxygen sensor unit, Go to "Final DTC Checking"  procedure.

   NG 

   The Downstream oxygen sensor cannot be determined as the cause of failure.

   If the fault code reoccurs, reinstall the previous oxygen sensor and Go to "Final DTC Checking"  inspection for PCM procedure in the item.