Inspection Procedure

1. Turn ignition to OFF position, and then disconnect HO2S and ECM connector.
2. Measure resistance between terminal 4 of the HO2S harness connector and 9 of the ECM harness connector.

   Specification (Resistance): below 1Ω

   Fig 1: Checking For Open In Harness

   Courtesy of KIA MOTORS AMERICA, INC.

Does the resistance indicate continuity?

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

1. Turn ignition switch to OFF position, and then disconnect HO2S and ECM connector.
2. Measure resistance between terminal 4 of the HO2S harness connector and chassis ground.

   Specification (Resistance): infinite

   Fig 2: Checking For Short To Ground In Harness

   Courtesy of KIA MOTORS AMERICA, INC.

Does the resistance indicate open?

1. Yes:  Go to next step.
2. No: Repair short or short to chassis ground in harness.

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 4 of the HO2S harness connector and chassis ground.

   Specification (Voltage): below 0.5V

   Fig 3: 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.

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

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