DTC Code P0420 - catalytic convertor efficiency below threshold. Bank 1

[amin_kundi]

I got the code. P0420 and i am confused what to do.
I own suzuki alto JDM japanese import 2010.
Its check engine light is on. And the error is the same.
What to do?
Change O2 sensor. Front
Change O2 sensor. Back
Change Catalytic Convertor

Or any other safe and economical way to get solution to this issue.

I also want to mention that. My car goves upto 21km/l on highways. BUTTT... it gives only and only 13-14km/l in local traffic.
I do not want to compromise on fuel economy. Rather i want to increase the local fuel efficiency.
The car pick is normal/satisfactory. (jaisay sab 660cc hotay hain)

[ab6666]

Try by cleaning the CAT if it doesn't work then change it but please donot remove it.

[amin_kundi]

thank you so much for your kind opinion abdullah. do you have the same experience. As i have gone through dozens of forums and blogs.
some says, CAT can be cleaned with acid....
some says its compact and can not be worn out, it can not be cleaned...
some says O2 sensors must be the problem...

i have no issue with the MIL engine check light,
I just want my fuel economy of the care be same as it does on long routes 21km/l
it gives me only 13-14 km.l in local peshawar traffic with AC ON

[ab6666]

There are number of shops that are cleaning the CAT give it a try . If a CAT is badly choked cleaning will improve the fuel average as well as acceleration
Most of the people on this forum has reported improve fuel efficency after cleaning a choked CAT.
CAT does wornout it is a replacable item.

[amin_kundi]

thank you for your kind advice, i will give it a tr and will post feedback. in the meanwhile i am waiting for other guidance as well.
and anyone whom have this Alto Japanese 660cc 2010 and above model with the same code.

[kashi.m46]

bro what did u do to fix this problem i also have the same one and alto 2013 model 660cc

[pwuser155860696358]

Respected sir. I have suzuki alto 660cc japane its check light on after 3to5km its check light begin bubling its ac stop and missing frequently become hard.i changed its front oxygen sencor washed its silensor two days run smoothly 3rd day its previous state now i changed its coils set .after one week again check light on and bubling missing ,hardness after computer p0420 code occur . I am much confussed kindly help me , guidr me .is there any your spot in multan thank you