Code P0420, Oxygen Sensor?

Hi,

Here is a link that explains how to check/test an O2 sensor using a voltmeter/multimeter. Also, if you have a live data scan tool, you could watch the voltage signals from the sensor. It should be between 0.1v and 1.0v and jump when the throttle is pressed.

Here is the link that explains how it can be done with a multimeter:

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

I hope this helps. Also, in most cases, the code you have indicates the catalytic converter has failed.

Let me know what you find or if you have other questions.

take care,

Joe