Check the following items and repair as necessary:
- Check for fuel contamination.
- Check for use of improper sealant.
- Check for engine oil/coolant consumption
- Inspect HO2S for silicon contamination from fuel or use of improper sealant. The HO2S may have a white powdery coating and this will result in a high but false voltage signal (rich exhaust indication)
Was a problem found in any of the above areas?
YES
Repair as necessary and go to "Verification of Vehicle Repair" procedure.
NO
Test with a new HO2S and check for proper operation. If problem is corrected, replace HO2S.
And go to "Verification of Vehicle Repair" procedure.