Check HO2S
- Ignition switch is turned "OFF". Disconnect HO2S connector.
- Check that the HO2S is securely installed.
- Check the HO2S for contamination or damage, water intrusion in connector, incorrect fuel pressure, VAC leaks.
- Is the sensor normal?
YES
- Go to "CHECK THE SIGNAL WAVEFORM OF HO2S " as 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.