Exhaust leak the culprit?

[Loekee75]

Does anyone know if an exhaust leak between the manifold and cat converter can and/or will set an open 02 sensor circuit (code 13)? After replacing the sensor, and even tracing the wire all the way to the ECM, I've found that the circuit is fine...but I'm still getting the code My concern is what seems to be an exhaust leak near the cat converter, I can smell the exhaust, slightly hear it escaping at idle, and at all speeds there is a slight hum, louder than what a "normal" buick should sound like! If it's possible that this exhaust leak is constantly throwing off the 02 sensor's readings to the ECM, then that'll certainly narrow things down for me!