Sorry to bring up a very old thread. Having this exact same issue on a 2007 SX4. Car has brand new oxygen sensors, both the air fuel ratio sensor and sensor 2. Sensor 1 is a denso and sensor 2 is an NTK. Monitoring voltage on the brown wire at the oxygen sensor key one engine running, it starts out at 4.4v, it will eventually drop down below 1.0v but it takes probably around 2 minutes to do so. As I understand it this code will trigger if it sees over 1.2v for more then 5 seconds. We have tried a different pcm with the exact same issue, not sure what is going on here, checked continuity on the power wire to the sensor and it is good, has no voltage drop, checked all the grounds on the pcm, running out of things to try.