Inspection Procedures

1. Thoroughly check connectors for loose, poor connection, bent, corrosion, contamination, deterioration or damage.

Are all connectors good? 

Yes: Go to next step.

No: Repair or replace it.

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

Fig 1: Measuring Voltage Between Terminal 1 Of HO2S Harness Connector & Chassis Ground

Courtesy of HYUNDAI MOTOR CO.

• Specifications: below 0.5V 

Is voltage within specification? 

Yes: Go to next step.

No: Repair short to power in harness.

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

• Refer to  SIGNAL WAVEFORM   for more information. 

Is the rear HO2S signal normal? 

Yes: Proceed with ECM PROBLEM PROCEDURE .

No: Replace HO2S.