Inspection Procedures

1. Connect Hi-Scan (Pro) to data link connector and warm up engine to normal operating temperature.
2. Using Hi-Scan (Pro), monitor HO2S signal.

Does the HO2S signal switch from lean to rich or from rich to lean? 

No: Go to next

Yes: Problem is intermittent or was repaired and engine control module memory was not cleared. Proceed with INTERMITTENT PROBLEM PROCEDURE  .

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

Are all connectors good? 

Yes: Go to next

No: Repair or replace it.

1. Turn ignition switch to OFF and disconnect ECM connector.
2. Turn ignition switch to ON.
3. Measure voltage between 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.

• Specification: below 1ohm 

Does each resistance indicate continuity? 

Yes: Go to next

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 

Does the HO2S signal switch from lean to rich or from rich to lean? 

Yes: Proceed with ECM PROBLEM PROCEDURE  .

No: Replace HO2S.