2001 Toyota Corolla p0420

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TINKERSTINKER87
  • MEMBER
  • 1 POST
2001 Toyota Corolla 4 cyl Automatic

took car for emissions test failed due to this P0420(bank1)(5) ?
Aug 2, 2010 at 3:49 AM
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MMPRINCE4000
  • ✓Experienced Mechanic
  • 8,548 POSTS
It is a cat. effeciency below threshold error.

Downstream O2 sensors measure CAT effeciency. Problem could be CAT itself or O2 sensor.
Aug 4, 2010 at 12:35 AM
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