P0420 code

Tiny
PALERO
  • MEMBER
  • 2002 HONDA CRV
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 109,000 MILES
What sensor do I have to replace with p0420 code my car
Wednesday, February 16th, 2011 AT 12:19 AM

5 Replies

Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Hello,

This code Catalyst System Efficiency Below Threshold (Bank 1) is because the catalytic converter is worn out here is a guide to help walk you through the replacement with diagrams below to help you with your car.

https://www.2carpros.com/articles/catalytic-converter-replacement

Check out the diagrams (Below). Please let us know if you need anything else to get the problem fixed.
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Wednesday, February 16th, 2011 AT 12:27 AM
Tiny
JOEY LITTLE
  • MEMBER
  • 1 POST
  • 1999 HONDA CRV
  • 4 CYL
  • AWD
  • AUTOMATIC
  • 150,000 MILES
I have a code p0420 that says catalyst efficiency below threshold(bank 1). What is this?
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Wednesday, February 13th, 2019 AT 8:10 PM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Usually a faulty O2 sensor will throw this code. Need to check your oxygen sensors. Follow the link below to learn how to test an oxygen sensor.

https://www.2carpros.com/how_to/how_to_test_oxygen_sensor.htm

If sensors are OK, need to flow test the catalytic converter..

Thanks for using 2CarPros.com!
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Wednesday, February 13th, 2019 AT 8:10 PM (Merged)
Tiny
EGUZMAN72
  • MEMBER
  • 1 POST
  • 1999 HONDA CRV
  • 4 CYL
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
What does this code mean? I think it needs a regular maintenance but I am not sure.
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Wednesday, February 13th, 2019 AT 8:10 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Hi eguzman72,

P0420 = Catalyst efficiency below threshhold.

Usually this means the catalytic converter is bad. It is not a regular maintenance item.
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Wednesday, February 13th, 2019 AT 8:10 PM (Merged)

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