Check the Signal waveform of HO2S

1. Ignition switch is turned "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.

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4. Is the sensor switching properly?

YES 

• Substitute with a known-good ECM and check for proper operation. If the problem is corrected, replace ECM 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.