Question about Mitsubishi Montero
THAT USUALLY MEANS THE CATALYTIC CONVERTER IS DEFECTIVE ON THE SIDE THAT CYLINDER NUMBER 1 IS ON. IT NEEDS TO BE REPLACED. THE CODE PROBABLY SAID THE EFFECIENCY WAS BAD.
Posted on Aug 04, 2010
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Posted on Jan 02, 2017
This code has plagued technicians nationwide. This code is set because the computer is not reading the proper signals from the O2 sensors. This could either be related to faulty sensors or just a weak catalytic converter. There is also other solutions where you can dampen the O2 sensor signal but it's extremely difficult for a do-it-your-selfer to do.
Posted on Sep 03, 2009
put a new rear O2 sensor and it fixed it. Only problem you might have is if you have an aftermarket downpipe. If it is Catless then you are going to need some type of tune, opensource, Cobb AP, etc.... Even if it is a high flow cat then you will still need a tune because it will throw a code 75% of the time. If your stock cat is still on then replace your rear O2 sensor and that should fix it. Could be something else but mine was the exact same problem.
Posted on May 29, 2010
SOURCE: check engine light code is
There is not a problem with a sensor there is a problem with the catalytic converter. P0420 sets when the downstream o2 sensor is either reading higher than expected or reading simular to the upstream O2 sensor. Either way it is usually the catalytic converter that is the source of the problem and rarely the downstream O2 sensor.
The Catalytic converter is located in the exhaust system under the car. Catalytic converters from either the dealer or a quality direct fit part from a reputable manufacturer are recommended. Cheap cats lead to lots of problems!
Posted on Feb 13, 2011
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