suzuki aerio 2004 light on code po420

Question

Rrplace sensors both of them keeps showing 420

Answer 1

Hi there,

Well this code is for a bad catalytic converter, so you might have replaced the sensors but if the converter itself is the source of the problem it won't help.

Also, if the engine isn't running well, or the plugs aren't burning the fuel clean, you could get this code because the converter can't get it all cleaned out.