SES code P0141

My SES light showed up a few days ago on my '97 GT. I had a friend pull the code. He siad it was P0141. He said that is the O2 sensor that is on bank 1 sensor 2. Is he correct and if so which O2 sensor does the code correspond to and where it is located. I believe there are 3 sensors, SENSOR,HTD OXY(POSN 1) in the exh manifold, and 2 that are SENSOR,OXY(POSN 3) post manifold, is this correct? This is based on the acdelco part list. But I am not sure which I need to replace. Please help.

Thanks
FB

Here is how the O2 sensor locations work.

Bank one is always the odd bank, bank 2 is the even bank.

Sensor one is the first one located closest to the engine, sensor 2 is the next one after sensor one. On most car engines with one manifold have only 2 sensors. One on the manifold is the engine management sensor and the other is after the cat which only monitors cat efficiency.

Bank one sensor 2 is the one mounted after the cat.

Thanks Flatrater. Are there 2 O2 sensors after the cat in the 97. AcDelco has 2 different part# for the after cat O2 sensors. People at the parts store were not sure. How can I determine which I need. The two part#'s were Afs116 and Afs97 and both described as SENSOR,OXY(POSN 3). Also could the p0141 code because by a bad cat or only a bad O2 sensor?

Thanks again
fb


Here is how the O2 sensor locations work.

Bank one is always the odd bank, bank 2 is the even bank.

Sensor one is the first one located closest to the engine, sensor 2 is the next one after sensor one. On most car engines with one manifold have only 2 sensors. One on the manifold is the engine management sensor and the other is after the cat which only monitors cat efficiency.

Bank one sensor 2 is the one mounted after the cat.

As far as I know their are 2 different part numbers one for sensor one and one for sensor 2. The only difference between the 2 is the connector (the plug end).

Only only used the GM sensors, so I can't tell you anything about the aftermarket ones.

Your P0141 code means you have a bad heater circuit on your sensor. A bad cat will not cause this code to come on. Usually a bad cat will give you a P0420 code. I would just remove your sensor take it to the parts store and match up the sensor, taking a close look at the connector end. Yours should be more of a square connector (2 rows of 2 wires). The other O2 sensor has 4 wires right in a row side by side.

This is a bad!

XX
XX
as looking into the connector you will see the wires arranged like this.

XXXX
this is the other sensor looking the same way.

thanks again