Inspection Procedure

1. Connect a Hi-Scan (Pro) to the data link connector.
2. Start engine and wait 1 minute.

Does scan tool display DTC P0138?

1. Yes:  Go to next step.
2. No: Problem is intermittent or was repaired and ECM memory was not cleared. See INTERMITTENT PROBLEM INSPECTION PROCEDURE ..

1. Turn ignition switch to OFF position, and then disconnect HO2S and ECM connectors.
2. Turn ignition switch to ON position.
3. Measure voltage between terminal 2 of the HO2S harness connector and chassis ground.

   Specification (Voltage): below 0.5V

   Fig 1: Checking For Short To Power In Harness

   Courtesy of KIA MOTORS AMERICA, INC.

Is voltage within specification?

1. Yes:  Go to next step.
2. No: Repair short to power in harness.

1. Reconnect the HO2S and ECM connectors.
2. Warm up the engine to normal operating temperature.
3. Using a Hi-Scan (Pro), monitor the HO2S signal waveform.
   NOTE:

   • 1.3V when signal line is short to battery line.

Do the rear HO2S signals fluctuate between 0V and 1V?

1. Yes:  Proceed with ECM PROBLEM INSPECTION PROCEDURE .
2. No: Replace HO2S.