1999 Pontiac Grand Am

1999 PONTIAC GRAND AM
Avatar
MRSNICH
  • MEMBER
  • 1 POST
1999 Pontiac Grand Am 4 cyl Automatic

Have a 1999 Grand Am trying to get it inspected. Code P0420 keeps coming up. Replaced oxygen sensor and P0420 is still coming up. What do I need to do really need car to pass inspection
Nov 2, 2010 at 10:03 AM
Advertisement
Avatar
WRENCHTECH
  • CERTIFIED EXPERT
  • 20,761 POSTS
That is a code for Catalyst efficiency on Bank1 and is an indication of a bad Catalytic Converter. I don't know why you changed an oxygen sensor.
Nov 2, 2010 at 10:21 AM