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The check engine light is on. I took it to have it smoged and the tech gave me a trouble code bank one system one. which he told me was the O-2 sensor before the cat. I changed the sensor, reset the computer, and drove it 25 miles. the light came back w/ the same trouble code. I read that a tech thought the voltage perameters were off. so my question is has anyone experienced this problem and what solved it.