Component Inspection

■ Upstream (S1) Heated Oxygen Sensor (HO2S) Visual Inspection 

1. Ignition "OFF" and disconnect HO2S upstream (S1) connector.
2. Check that HO2S upstream (S1) is not contaminated or damaged by foreign materials.
3. Does the HO2S upstream (S1) have any contamination or damage?

   YES 

   • Repair or replace as necessary and then, go to "VERIFICATION OF VEHICLE REPAIR " procedure.

   NO 

   • Carefully re-do this troubleshooting guide steps.
   • If problem still occurs, replace HO2S upstream (S1) and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.