Visually/physically inspect the following items:

- Ensure that the HO2S is securely installed.

- Silicon contamination. This contamination will be indicated by a white powdery coating on the portion of the sensor exposed to the exhaust stream and this will result in a but false(high) voltage signal

- Fuel, engine coolant or oil contamination

- Use of improper sealant

- If contamination is evident on the HO2S, Fix the source of the sensor contamination before replacing the sensor to prevent future contamination. Go to "Verification of Vehicle Repair" procedure.

Was a problem found in any of the above areas?

	▶ Repair the connector. Go to "Verification of Vehicle Repair" procedure.
	▶ Substitute with a known-good component and check for proper operation. If the problem is corrected, replace component and then go to "Verification of Vehicle Repair" procedure.