I have a 2005 camry with a 2.4 ltr engine and 124000 miles. My chech engine light came on about 500 miles ago. I hooked up a OBDII code reader to my car and got back P0420 on the first O2 sensor and pending on the second O2 sensor. I went to toyota and purchased both sensors and installed them. I reset the check engine light on my car. car ran about 60 miles check engine light came on again. I reset check engine light one more time after about another 50 miles check engine light comes on again. both time same engine code P0420, just like before. I doubt it is a faulty sensors, any ideas on what it could be. TIA

Check here:

http://www.iequus.com/support/obd2_definitions.php

Also, download the generation 5 factory service manual stickied at the top of this forum. It should have a more specific test tree for that trouble code.

Mike

You may have a bad cat converter. It should fall under the emissions warranty.
http://www.obd-codes.com/p0420