Confirmation Test
WARNING: This page is about a different car, the 2003 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
Connect Lexus scan tool to Data Link Connector (DLC) No. 3. See Figure. Ensure all accessories are turned off. Start and warm engine to normal operating temperature. Increase engine speed to 2500-3000 RPM for 3 minutes. Using Lexus scan tool, ensure heated oxygen sensors (bank No. 1 and 2, sensor No. 1 and 2) feedback to ECM fluctuates around .5 volt. See Fig 1.