2000 Mazda Protege code P0420

Tiny
ZEMORZEMOR
  • MEMBER
  • 2000 MAZDA PROTEGE
  • 1.6L
  • 4 CYL
  • FWD
  • MANUAL
  • 160,000 MILES
What causes this code and how to diagnosis the causes?
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Wednesday, April 1st, 2015 AT 10:30 PM

10 Replies

Tiny
WRENCHTECH
  • EXPERT
The means that the Catalytic Converter for bank one is not doing it's job correctly. On rare occasions a leak in the exhaust can cause that code but 95% of the time that is a bad Converter.
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Thursday, April 2nd, 2015 AT 2:19 AM
Tiny
ZEMORZEMOR
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There is black sooth in the exhaust do you think its clogged?I want to figure out why the cat is bad before I put a new one.

What can causes a cat to go bad thank you
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Thursday, April 2nd, 2015 AT 8:55 AM
Tiny
ZEMORZEMOR
  • MEMBER
There is black sooth in the exhaust do you think its clogged?I want to figure out why the cat is bad before I put a new one. I checked the temperature of the converter at the outlet it was 540 F

What can causes a cat to go bad

thank you
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Thursday, April 2nd, 2015 AT 2:03 PM
Tiny
WRENCHTECH
  • EXPERT
Any sort of contamination from a malfunctioning engine will take out a Cat. If you have any misfiring or coolant being burned, that will contaminate it. Just seeing black soot doesn't mean much. All exhaust has soot in it.
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Thursday, April 2nd, 2015 AT 3:02 PM
Tiny
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Ok so I need a scan tool to do that. What is the most best Pc scan tools that I can get?
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Friday, April 3rd, 2015 AT 8:08 AM
Tiny
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  • MEMBER
I put a bottle of techron fuel system cleaner and the check engine light did not come back. All monitors are ready. What you think?
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Tuesday, April 7th, 2015 AT 9:42 PM
Tiny
WRENCHTECH
  • EXPERT
There is no such thing as "Mechanic in a Can". It will be back.
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Wednesday, April 8th, 2015 AT 1:58 AM
Tiny
ZEMORZEMOR
  • MEMBER
What is the first thing that I need to check first before I replace the catalytic
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Thursday, April 9th, 2015 AT 8:05 AM
Tiny
WRENCHTECH
  • EXPERT
For any leaks in the exhaust near the converter.
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Thursday, April 9th, 2015 AT 8:48 AM
Tiny
ZEMORZEMOR
  • MEMBER
The check engine light went off now. Is this normal and what could causes it?
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Sunday, April 26th, 2015 AT 10:31 AM

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