1998 Chevy Silverado ENGINE DIAGNOSTIC CODES

1998 CHEVROLET SILVERADO
177,000 MILES • V8 • 2WD • AUTOMATIC
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TOMHAYES
  • MEMBER
  • 1 POST
I HAVE 2 CODES FOR MY TRUCK. THEY ARE:
P0420 AND P0430

Catalyst System Efficiency Below Threshold (Bank 1)
Catalyst System Efficiency Below Threshold (Bank2)

Can you tell me what needs to be done to correct these codes? I had a new Catalytic Converter installed 1 year ago. Thanks for your help.
Mar 8, 2008 at 7:54 PM
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BLACKOP555
  • ✓ASE Certified Mechanic
  • 10,386 POSTS
  • ASE Certified Mechanic
those codes are for bad cat's.

firrst thign to check is to see if the sensors are good, if they are bad replace them. also you may have a exhaust leak causing those codes to appear.
Mar 9, 2008 at 10:10 AM
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