P0420 Jeep -

Question

what is po432 po420 codes on 04 grand Cherokee 4.7 engine

Answer 1

As the code description implies the P0432 code means that the vehicle's control module has detected that the three-way catalytic converter is not working properly (is not as efficient as the factory is expecting). Replacing the oxygen (O2) sensors may sometimes fix the code, but in most cases the catalytic converter needs to be replaced to fix the problem. If the P0432 code is combined with other codes, try fixing the other codes first.

https://www.autocodes.com/search_codes.php?q=po432

I would use 91 octane fuel from Shell and do an intake flush and reset the code, you may have a lot of carbon build up inside the catalytic converter. And drive the car a little hard to get the catalytic converter hot enough to burn all the carbon build up out of the exhaust.

see diagnostic procedures below