Circuit/System Verification
WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
- Allow the engine to reach operating temperature. With the engine running, observe the affected HO2S parameter with a scan tool.
- The HO2S 1 value should vary from below 200 mV to above 800 mV and respond to fueling changes.
- The HO2S 2 value should change more than 200 mV when the throttle is quickly cycled 3 times from Closed to Wide Open and back to Closed after running the engine at 1500 RPM for 30 seconds.
- If any HO2S heater DTCs are set, diagnose those DTCs first.
- The affected HO2S may be damaged due to contamination. Prior to replacing the affected HO2S, inspect for the following sources of contamination:
- A silicon contaminated HO2S
- Fuel contamination-Refer to Alcohol/Contaminants-in-Fuel Diagnosis .
- Engine oil consumption-Refer to Oil Consumption Diagnosis .
- Engine coolant consumption-Refer to Loss of Coolant .
NOTE: Refer to Silicon Contamination of Heated Oxygen Sensors Notice .