P0420 Toyota - do i have to change just the catalyzed or the sensors

Question

My toyota corolla 09 has p0420 code on do i just change the sensors or the catalyzed

Answer 1

Hi there,

Normally you will have to replace the converter. Sometimes the rear O2 sensor can cause this code to come on. Without a scan tool to watch the sensor though it's difficult to tell.

If you are in the US the converter is covered with a 8yr/80,000 mile warranty and will be replaced by the dealer at no charge if it is bad.