Component Inspection

■ Check HO2S 

1. IG "OFF". Disconnect HO2S connector.
2. Check that the HO2S is securely installed.
3. Check the HO2S for contamination or damage, water intrusion in connector, incorrect fuel pressure, VAC leaks.
4. Is the sensor normal?

   YES 

   • Go to "Check the Signal waveform of HO2S" below.

   NO 

   • Substitute with a known - good HO2S and check for proper operation. If the problem is corrected, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

■ Check the Signal waveform of HO2S 

1. IG "OFF". Connect HO2S connector.
2. Connect probe to HO2S to measure signal waveform using oscilloscope function. Start engine.
3. After warming-up, monitor signal waveform of HO2S with GDS.
   Fig 1: Screen Display - Normal Waveforms Of Front HO2S (Upper) And Rear HO2S (Lower) (Chassis Ground Used)

   Courtesy of HYUNDAI MOTOR AMERICA
   Fig 2: Screen Display - Normal Waveforms Of Front HO2S (Upper) And Rear HO2S (Lower) (Sensor Ground Used)

   Courtesy of HYUNDAI MOTOR AMERICA
4. Is the sensor switching properly?

   YES 

   • Substitute with a known - good ECM (PCM) and check for proper operation. If the problem is corrected, replace ECM (PCM) and go to "VERIFICATION OF VEHICLE REPAIR " procedure.

   NO 

   • Substitute with a known - good HO2S and check for proper operation. If the problem is corrected, go to "VERIFICATION OF VEHICLE REPAIR " procedure.