po420

I have a 1994 ford mustang
and I have a check engine light that comes on every now and then.

i did a test thing and it gave me the code

po420.

the car runs fine its just the check engine light comes on.



I don't know anything about cars, this is my first one.


Thanks for any help!
-Mike.

Welcome to AF. P0420 is catalyst system below threshold.