2002 Sunfire question

My check engine light came on recently so I hooked up a code reader and received code P0130 -> O2 Sensor Circuit Malfunction (Bank 1, Sensor1). From my understanding there are two Oxygen sensors, 1 on the manifold (upstream) and the other placed after the catalytic converter (downstream), but I do not know which one code P0130 is referring to. Can anyone assist? Am I looking at the correct sensors? My guess is that this needs to be replaced, as all wiring looks good. Any other suggestions as to what might be causing this issue?

Thank You,

Spec36

the OnBoard Diagnostics II (2) system is one dianostics system to be used on all engines since 1995.4 cyl, straight 6 cyl., V/6, v/8, V/10, etc. It's a little confusing but as far as O2 sensors are concerned each engine bank has 2... a primary ( sensor 1) before the catalytic converter, and a secondary ( sensor 2) after it. Bank 1 is always the bank that contains the number 1 cylinder. So, since a straight 4 cyl has only one bank it will always be read as Bank 1. So really all you have to remember is #1 = before and #2 = after .

Thanks for the reply.