2001 Cadillac Catera eng code

Hello
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You may have a faulty oxygen sensor. Located on the exhaust, under vehicle, usually more than one oxygen sensor.
However, it is probably more complex than that. I suggest checking the pipe that connects to the exhaust manifold. If it has cracked then the secondary air will not be forced into the exhaust stream which will prevent the oxygen sensors from sensing the correct flow.

Hope this helps.
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