Code P0420 questions
#1
Code P0420 questions
I am getting a P0420 code. From the looks of things it is supposed to be either a downstream 02 sensor or bad catalytic converter. I am assuming the downstream 02 sensor is behind the cat. Are there 2 cats and 2 downstream 02 sensors. Just not sure how to verify what exactly is the problem. The car is a 99 with about 195,000 miles. Any help or ideas.
Thanks
Thanks
#3
Possible causes:
Faulty three-way catalyst converter bank 1
Exhaust tube
Intake air leaks **
Faulty oxygen (O2) sensor **
Faulty fuel injector(s)
Leaking fuel injector (s)
Faulty spark plugs **
Improper ignition timing
Faulty engine control module (ECM)
Dirty air filter **
(**) Check/replace these first-off-the-bat.
Faulty three-way catalyst converter bank 1
Exhaust tube
Intake air leaks **
Faulty oxygen (O2) sensor **
Faulty fuel injector(s)
Leaking fuel injector (s)
Faulty spark plugs **
Improper ignition timing
Faulty engine control module (ECM)
Dirty air filter **
(**) Check/replace these first-off-the-bat.
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