Rear oxygen sensor can cause emissions failure on Toyota Avalon

The rear Oxygen sensors are a critical element in fuel control (unlike other vehicles) and can cause an emissions test failure for high CO and HCs. The sensing element cracks and and reports an erroneous steady state lean condition which confuses the computer, which in turn makes the fuel mixture overly rich.

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Average mileage: 45,000 (45,000–45,000)
4 model years affected: 1995, 1996, 1997, 2007 more
6 people reported this problem
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