My 09 Corolla has the same problem with the "check engine" light coming on, as well as the traction control flashing on and off. I have change the Bank1 sensor 1 unit three times, as well as the bank2 sensor 2 downstream unit, still pops on lights 20 seconds after clearing code with OBD2 reader. Is this the ECM, and is there a recall for this problem? Read that there is a fuse for this system, but where in the fuse block? Does not affect operation of the engine at any time.