Diagnostic Aids
WARNING: This page is about a different car, the 2009 GMC Sierra and 2009 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.
Inspect the OSS, harness, connector and control solenoid valve assembly pins for metallic debris and output shaft machined face for damage or misalignment. Proper torque of the OSS mounting bolt is critical to proper OSS operation. Use a terminal test kit for any test that requires probing the control solenoid valve assembly harness connector or a component harness connector.