When this code comes, it means that the catalytic of the vehicle is
low response and why does it the low response that catalytic is dirty.
Catalytic must be washed with a cleaner after every 30,000 km drive if you cannot wash it with a cleaner.

works.

In the catalytic, the exhaust of the engine is stored and the oxygen sensor gases are collected, which are being told to the computer
by sensing the oxygen sense And adjusts the fuel mileage by injecting that accordingly with the computer injector.

location:

The location of the catalytic is either in the middle of your exhaust or is placed on the front, inside which there is a soil damp .

How To Fix P0420:

For this first of all you have to try to wash your catalytic if even after that your issue is not solved then change the oxygen sensor.
Check the exhaust is leaking from anywhere and after that in the there is catalytic damage from inside So fix it on the and then check your code will also be clear of p0420.

Oxygen sensor:

Oxygen sensor is also divorced with catalytic if the oxygen sensor is malfunctioning or will have a low response If the low respond
then the code of p0420 will come because the efficiency of the catalytic will not be censored by the proper oxygen sensor.
Check by changing the oxygen sensor Your issue can be solved code on P0420 can be over.

Wash Catalytic:

There are two ways to wash catalytic one is to put Liqui molly Catalytic Cleaner in the feul tank and keep it curd at 2500 to 3000 rpm .
And 150 to 200 km drive should be done with this gets washed catalytic your issue is solved by p0420 end .
Another way is to take off the catalytic and soak it in it for 10-12 hours with detergent.