New to the forums, and thanks in advance for any assistance.

'01 Blazer, 2WD, Vortec 4300, V6

Recently pulled the code PO141 for O2 sensor Bank 1, Sensor 2 malfunction. Unfortunately, I'm having problems finding the darn thing. I'm aware that Sensor 2 is a post-converter sensor, but I only actually see one of them past the converter. There are two sensors ahead, one on the left side connected to the bottom Y-junction pipe (I believe Bank 1, Sensor 1), and one on the right along the top Y-junction pipe (I believe Bank 2, Sensor 1). Are there only 3 sensors on my vehicle, or am I just flat out not looking in the right spot?

Any help would be greatly appreciated. I'm afraid that I'm a bit of a novice to this do-it-yourselfing. Thanks.

 

You are correct, B1S2 is the post cat sensor. It got confusing when the '96-'97s had 4 sensors and had B1S2 ahead of the catalytic converter and B1S3 behind it.

And yeah, typically this is a faulty heater in the O2 sensor, but I would have the codes cleared (either go to Autozone/Advanced Auto, or disconnect your battery for 10-15 minutes) and see if it comes back. Inspect the wiring for corrosion or wear as well.

 

Thanks for the help. I read the code over at AutoZone, so went ahead and cleared it then. I had gotten confused reading all the different literature out there saying that I had 4 sensors, but there's clearly no need for another post-converter sensor with only single exhaust.