P013A or P013C
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The ECM determines that the response time for the HO2S 2 to switch from greater than 400 mV to less than 200 mV is greater than 1 second. The condition exists for greater than 4 seconds or for a cumulative time of 30 seconds.