Question about 2003 Toyota Camry
2003 Camry code P0420 Catalytic converter fault what can I do?
That code is saying that your catilitic converter is junk, but could be caused by some other problem also gas leak on exhaust system a/f sensor bank 1,2 sensor 2. heated oxygen sensor bank1 sensor 2, or the three way catilitic converter. these are the listed reasons for that code being thrown, to tell you the truth its not really that big of a deal ya know, i mean its just emissions, either the cat is bad or the oxygen sensor is bad in my opinion will it hurt the car? no, will that little light annoy the **** out of you? YES ; ) because the sensor is behind the cat it will not have any imput into your computer to change fuel maps or anything, the post sensors are only for reading if the cat is good or not, i actually cut mine off and the cat, the check engine light might always be on, but if my car messes up for some other reason then i will feel or smell it and dont really need the dummy light yea know? anyways its your choice to live with it or to take it to the shop and have your sensor tested/cat looked at, either way it wont hurt your car, if your front o2's start going bad you have to change those, but not the post cat one. dont let those shop guys bully ya into spending to much tell me what they say cause there always after an unsuspecting person's wallet, thats why i opened my own shop.
if this helped throw some blue/fix ya rating.
take care have a good day
Ez Automotive/U.S. Army
Posted on Sep 13, 2008
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Posted on Jan 02, 2017
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code PO420 you have is Catalyst System efficiency is below threshold bank one.
Usually replacing the O2 sensor that's the front most in the exhaust system
will cure your problem,
Your Check Engine light
is on and you find a P0420 code for a catalytic converter fault. Does that really
mean your converter has reached the end of the road and needs to be replaced? A
new converter can cost $600 to $1000 or more if a new car dealer or repair shop does the
job, or maybe half that amount if you do it yourself. It's an expensive fix
that may or may not be necessary. The problem, in most cases, is an emissions
issue, not a performance issue that affects the way the engine runs.
A P0420 diagnostic
trouble code is a "generic" fault code that is set when the Onboard Diagnostic II
(OBD II) system sees a drop in converter efficiency. The
OBD II system monitors catalyst efficiency by comparing the switching activity
of the upstream and downstream oxygen sensors in the exhaust. The upstream O2
sensor in theexhaust manifold reflects the
condition of the exhaust gases as they exit the engine. The downstream O2
sensor in or behind the catalytic converter reflects the condition of the
exhaust after it passes through he converter.
The catalytic converter
is like an after-burner. It oxidizes (burns) any residual fuel vapors (unburned
hydrocarbons or HC) in the exhaust. It also burns any carbon monoxide (CO) in
the exhaust. The exhaust must meet federal emission standards, and if a problem
exists that causes emissions to exceed the federal limits by 150%, the OBD II
system is supposed to catch the fault, set a code and turn on the Check Engine
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