Lexus Troubleshooting Questions? Ask a Lexus Expert
99% of the time this is a bad catalytic converter for bank two. If the oxygen sensor was not working the computer would not know how to detect whether the efficiency of the converter was any good. Does your scan tool give you a voltage output of the rear or post catalytic converter oxygen sensor for bank two? If it does monitor that voltage hold the engine RPM at 3000 RPM the voltage should stay around .5 V and slightly rise and fall as you accelerate or did accelerate. If it constantly toggles between .1 V and .9 V then the converter is bad. You need to get the converter and the sensor pretty hot in other words operating temperature preferably drive the vehicle and monitor that sensor voltage.