P0420 Infiniti -

Question

Hello I have a Infiniti g20 2001 the code is p0420
With check engine light on and I replace O2 sensor already
And the light still on the car run strong with no loss of power
And no smell from exhaust please help me to identify this problem
Can the catalytic converter be cleaned

Thanks

Answer 1

P0420 Catalytic system efficiency below threshold

Yes it can be, and  the best way to clean it is to a have a clean running engine. this mean sparkplug should be in good shape, a clean airfilter, properly working front 02 sensor and the rear 02 sensor Alot of time P0420 where set by false catalytic codes due to poor maintance

 Here is vehicle that has a P0420 the sparkplugs are worn , worn sparkplug do lean the engine combustion cylinder out and as a result Hydrocarbon which is unburnt fuel rapidly degrade the catalytic and can set a P0420 worn sparkplug can set a false P0420.

Here is a scan tool data with a graphing capabilty. at 1500 RPM in nuetral there is activity in this case too much when a good working catalytic would stay above the 650 ml volt or above 450 ml volt , when it goes below it considered below threshold.

Some catalytic go through its usefull life here the catlytic just blew apart all the element broke apart.