Cel P0430

[ganny]

3 months ago, after receciving Error Code P0057 (Oxygen sensor heater control circuit low 22), I replaced my Bank 2 Sensor 2 oxygen sensor. I used a Bosch universal sensor available at my local AutoZone. The replacement worked and my CEL did not come back on.

Now, 3 months later, my CEL came back on. This time is was Error Code P0430 (Catalyst efficeincy below threshold- bank 2). Based on my research, this could be a bad catayltic converter, but is it usually a bad oxygen sensor (the same sensor I just replaced 3 months ago). Would it make sense for the new oxygen sensor to fail that quickly? My 2003 Lexus GS300 has 95,000 miles. Thanks

[intakerGS]

It's hard to say if the universal sensor is to blame, although I would advice to use OEM/Factory sensors only (Lexus is known for some very specific readings). Sensors going bad in three months isn't very common.

State of the catalytic converter depends on driving behaviour, for example, many short trips, additives in fuel, leaks etc. Even so, not my first suspect.

You might have an exhaustleak and I suggest you inspect this first. Next step is to measure voltage at the oxygen sensor on Bank 2 and check the wiringharness.