When the Chevy Equinox displays a p0420 fault code, this indicates a bad oxygen sensor. Replacing the responsible oxygen sensor will usually make this code go away. In some more serious cases, the muffler of the car might need to be fixed or replaced to get rid of the code. Exhaust manifold with leaks in them could also trigger this code, so welding the leak will typically resolve this. In some cases, a catalytic converter can cause this code to appear. This is actually a pretty common cause for it. Driving Your car with this code active is generally not a safety issue, but should be addressed immediately.
I have a 2011 Chevy Equinox. I have replaced both sensors twice, the catalytic converter twice and replaced muffler once. If I stop too fast I still get the check engine light, it is always code P0420.
Jay D.
April 9, 2020
On a chevy equinox, code p0420 typically means that an oxygen sensor isn't working properly, and that will usually be the only problem with this code.
Bradley R.
August 11, 2022
I've had the same problem from what I have researched and combination of symptoms I believe its actually just a clogged pcv valve which can cause all kinds of problems with pressure build up
I have that code on my wife 2010 equinox change cot because it was really clog light came back two days after i change o2 sensor still came back i realize the temperature sensor not pasting 86 i change sensor problem is still there can any help
Tim
November 11, 2022
I get the P0420 code about every 6 months. I buy the Dura Lube catalytic cleaner ($20) and just add it to the gas. Within a week or two, the light goes off. I also try to buy top tier gasoline as much as possible, to keep the fuel system clean. Where I live, top tier gas is the same price as the "cheap" stuff.
leonel
September 25, 2022
Tengo una equinox 2020 y se prende la luz del motor y indica ese código pero de repente se apaga sola y prende
pablo
June 4, 2023
P0420 definition catalyst system efficiency below threshold bank one
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