Camaro zl1 2020 code saying P0420?

Tiny
SOLO987
  • MEMBER
  • 2020 CHEVROLET CAMARO
  • 6.2L
  • V8
  • TURBO
  • 2WD
  • MANUAL
  • 37,000 MILES
Well I have been having problems with knock sensors. On both bank 1 and 2 and now I got a code saying p0420. And I have headers and a cold air intake on it.
Friday, September 5th, 2025 AT 5:33 PM

3 Replies

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Did you remove the catalytic converters? If so this will be the reason for the trouble code:

P0420 - Catalyst System Efficiency Below Threshold (Bank 1)

Please let me know.
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Saturday, September 6th, 2025 AT 4:29 PM
Tiny
SOLO987
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  • 2 POSTS
Yeah I did. Im running kooks headers
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Saturday, September 6th, 2025 AT 4:34 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
If you don't have cats you will have this code and the engine will not run at optimum performance. Believe it or not the engine is made to run at the best performance from the factory. Unless you plan a bunch of expensive engine and computer work is it best to leave it stock.
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Sunday, September 7th, 2025 AT 8:54 AM

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