2003 GMC Sierra Catalytic Converter problem

Tiny
JASONALL
  • MEMBER
  • 2003 GMC SIERRA
  • 4.3L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 170,000 MILES
My check engine light came on showing catalytic converter bad bank one. I replaced the whole Y-Pipe including both catalytic converters. I have reset the the light twice and driven around 250 miles already and the light is back on showing the same code? Am I doing something wrong here? My inspection is out and I need some advice quick. Is there a trick to getting the computer to reset? HELP!
Tuesday, June 10th, 2014 AT 6:03 AM

3 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Did you use OEM parts from the dealer?

Are there any exhaust leaks in the left pipe, even small ones?
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Tuesday, June 10th, 2014 AT 8:51 AM
Tiny
JASONALL
  • MEMBER
  • 2 POSTS
I ordered an after market y pipe and it didn't fit quite like the factory. But it fit. We did have some trouble getting it to seal though. I cant hear an obvious leak but that doesnt mean its not. Do you think that might be my problem?
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Tuesday, June 10th, 2014 AT 9:37 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Either one of those things could be your problem. The aftermarket parts often don't work and an air leak will effect the sensors.
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Tuesday, June 10th, 2014 AT 2:26 PM

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