2002 Pontiac Grand Prix Service Engine Light

2002 PONTIAC GRAND PRIX
131,000 MILES • 3.8L • V6 • AUTOMATIC
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BUSTER55555
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  • 3 POSTS
I replaced the o2 sensors and catalytic converter on my 02' Pontiac Grand Prix but the service engine soon light comes back on after I drive it around. I'm trying to pass emissions! What else could it be? As soon as I hit the 60 mile mark the light came on again.
May 9, 2014 at 2:45 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
What code are you getting and is it the same as what you got before the sensor was replaced?
May 9, 2014 at 2:52 AM
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BUSTER55555
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First code was for Cat Bank 1. Second time is was the same code so I had a new converter put it and replaced both sensors. this last time the code is P0420 Bank1.
May 9, 2014 at 3:09 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
Since you replaced both sensors and the converter, the problem is either in the wiring to the sensors (need checked while engine is running to see how they respond), in need of a tune up, you are dumping fuel from a stuck or worn injector, or the fuel pressure is too high. Have you pulled the plugs to inspect them?
May 9, 2014 at 3:47 AM
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BUSTER55555
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  • 3 POSTS
no, I have not. i'll do that. thanks for the help.
May 9, 2014 at 3:51 AM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
Let me know what you find.

If I don't hear from you, have a good weekend.

Joe
May 9, 2014 at 12:02 PM
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