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 step.

Yes: Problem is intermittent or was repaired and engine control module memory was not cleared. Proceed with HOW TO COPE WITH INTERMITTENT MALFUNCTIONS .

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. Measure resistance between the terminals 1 of HO2S harness connector and 14 of ECM harness connector C133-2.
3. Measure resistance between the terminals 2 of HO2S harness connector and 20 of ECM harness connector C133-2.

Fig 1: Measuring Resistance Between HO2S Harness Connector & ECM Harness Connector

Courtesy of HYUNDAI MOTOR CO.

• Specification: below 1Ω 

Does each resistance indicate open? 

No: Go to next step.

Yes: Repair open 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.