P0420 question.

I have a P0420 code and reading around it seems the best course of action is to just change the catalytic convertor , I would assume the same is true for a Safari as with other brands. I did not see however if there is a need to change the O2 sensors (new 2 years ago) or if there is a good way to test them ? Is there another possible cause I should be looking for ? 99 Safari with 240,000 km (150,000mi) running fine. Any input is welcomed ! :smile:

Are there any other DTC's set? If so, diagnose and repair them first. If not, P0420 is rather easy to diagnose using the flow chart.

Hi Oldmaster - No other dtc's set , please do tell how to use the flow chart for a diagnosis. I have a program on my laptop that gives readings of most of the sensors in real time. Thanks.

Send me your email address in a PM and I'll send the flow chart to you. Do you have dial-up or cable internet? The file is 4.11MB so if you have dial-up, I can reduce the size of the file.