Code p0420 reads on scanner

2002 PONTIAC GRAND AM
180,243 MILES
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BRIDGES2012
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  • 10 POSTS
P0420 reads on my 2002 Pontiac grandam V6. I recently had a head gasket job done (and Egr valve and thermostat and catalytic converter put on before the head gasket)I am trying to pass emission but my engine light keep coming on.Last week I replaced my EGR trying to get engine light to stay off so I can get my pass my emission.

Nice site :-) thanks!
Feb 8, 2012 at 12:50 PM
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MERLIN2021
  • ✓ASE Certified Mechanic
  • 17,250 POSTS
  • ASE Certified Mechanic
P0420 is the code for catalyst efficiency. Probably need a new one, and put new 02 sensors in while you're under it!
Feb 8, 2012 at 4:49 PM
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