Toyota Repair: 2002 RAV4 Oxygen Sensor, oxygen sensor, cat converter

Question
On the way to the Toyota dealer to have the ECM reprogrammed (recall SSC 60I) the check engine light came on (good timing???).  I thought it was most likely the problem described in the recall information, because it mentioned the check engine light coming on.  I was surprised to find out that an oxygen sensor needed to be replaced.  The diagnosis was PO161 O2 sensor heater circuit malfunction BK2S2.  This vehicle only has 52,000 miles on it; it seems a bit early for the O2 sensor to go bad.  I've driven the rav about 35 miles since the diagnosis and the check engine light hasn't come back on.  I'm planning on waiting for the  light to come back on before replacing the sensor.  If I end up needing to replace it, would it do any damage to the vehicle to drive a few months, about 1500 miles, before replacing it? Also, where is the bank 2 sensor 2 located? Thanks for your help.

Answer
Since the ssc 60I was done already I would wait to see if the check engine even comes back on at all, it may very well not, the #2 O2 sensor monitors the catalityc converter's performance, it is located just behind the cat converter, it doesn't harm anything to drive it with the rear O2 sensor inoperative, I really don't think the light will come back on after reprogramming the computer because the reprogramming changes the cat converter properties to make it more efficient.