Visually/physically inspect the following conditions :
- 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.
Warm up the engine to normal operating temperature and let it idle.
Connect GDSand monitor the O2 SNSR VOL.-B1/S1 parameter on the GDS data list
Specification : Refer to "Signal Waveform & Data" in the "General Information" procedure. Verify signal is switching from rich(above 0.45V) to lean(below 0.45V) a minimum of 3 times in 10 seconds (voltage will vary between 0.1 and 0.9V) at idle.
Is sensor switching properly?
 | ▶ Fault is intermittent caused by poor contact in the sensor's and/ or PCM's connector or was repaired and PCM memory was not cleared. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure. |
 | ▶ Go to next step as indicated below |
