Where Is Bank 1, Sensor 2 O2 Sensor on 2000 Buick Century 3.1 L Engine?

Maintenance/Repairs
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1

I have the trouble code titled Bank 1 Sensor 2 O2 Sensor Heater Circuit Malfunction. Can someone tell me what this means, where this O2 sensor is in my car, and what has to be done? It doesn’t sound like the trouble is in the sensor itself, but some wiring circuit in the car?

2

Bank 1 is on the same side as cylinder one on an engine.

Sensor 2 is the O2 sensor after the catalytic converter on bank 1.

Tester

3

Bank 1 on a transverse 3.1 V6 is the front set of cylinders. Since this car only has a single exhaust and a single catalytic convertor, B1 S2 O2 sensor is right behind the catalytic convertor. And there is no B2 S2 sensor for the other cylinder bank.

An O2 heater failure is common and won’t affect how the car runs. The heater is there to get the sensor up to operating temperature more quickly. Since it is only reading the effectiveness of the cat, it doesn’t really affect emissions.

4

From doing a little research and bad memory, I am thinking you only have two O2 sensors, one before the cat (either in the rear exhaust manifold or in the manifold to converter down pipe) and one after the catalytic convertor…

GM (and others) liked to use a front exhaust manifold (radiator side) and then run a crossover pipe (over top of the bellhousing) into the rear exhaust manifold(firewall side) then both banks exited the same rear exhaust manifold into a single down pipe before the catalytic convertor… The front exhaust manifold does not have previsions for an O2 sensor, and there are no previsions for an O2 sensor in the crossover pipe, that only leave 1 front O2 sensor before the catalytic convertor and 1 O2 sensor after the catalytic convertor…

Sooo short answer: one O2 before the cat and one O2 after the cat…

5

HO2SB1S2 is the sensor rearward, or after, or downstream from the catalyst.

This code sets when the ECM detects and open circuit or incorrect current flow through the heating element inside the sensor. More often than not the issue is a failed sensor. Other possibilities are a wiring issue between the ECM and sensor, or a blown fuse for the O2 heater (but why did the fuse blow in the first place?).