Hi, I have a bad rear O2 sensor and am going to order it online. However I don't know which side and all the online parts places sell them labeled as left or right units. Here are the trouble codes:

16440 - O2 Sensor B2 S2 P0056 - 004
17548 - O2 Sensor B2 S2 P1140 - 004

So B2 = Bank 2? S2 = Side 2?

Does anyone know if I am dealing with the left or the right?

Much obliged.

John