I have a 2002 Blazer 4 door and the check engine light has been on. My dad hooked up his computer to it and it returned code P0141 which I know is the o2 sensor bank1 sensor 2. I'm just not exactly sure which o2 sensor (I've seen them go from 38 bucks up to 100 bucks) to get and exactly where bank1 sensor2 is. I looked online with no avail.

Can someone point me in the right direction?

Thanks!

 

after searching around I found that I need to go with ACDelco parts. Part number AFS105 right? Will this one work? If so I'm going to order it and replace it myself.

Thanks!

 

P0141 Explained will give you some insight into the code you are receiving.

On the pre-98 trucks, B1S2 is the downstream pre-cat sensor which would be located after the "Y" in the y-pipe and before the catalytic converter. Your system should not have this sensor though. This is the post-cat sensor, located behind the catalytic converter.

Here is a picture showing the location of the O2 sensors on your exhaust:

This applies for all 98+ trucks even though it lists the post cat sensor as B1S3.

Looking up the PN from RockAuto.com, it shows a different AC Delco part number, 213-802. I would definitely stay with AC Delco.

 

thanks swart! I read one of yoru previous posts and saw the exact diagram. But searching on RockAuto I found I may need to get ACDELCO Part # 213802 instead. Can you recommend which one I get since its 2002 year? According to rockauto the Part number AFS105 only goes for up to 2001 years.

Thanks!

 

ok great! so based on that diagram, my bad sensor should be number 2? just wnat to be absolutely sure.

Thanks!

 

No, your bad sensor is #1 on the diagram. The post-cat (after cat) sensor. From 98 to mid-2002, this is listed as B1S3 because of the change that happened for the 98 model year. In mid-02, the MFI engine went in and they did away with the B1S3 nomenclature and just named it B1S2. So the item #1 in the diagram is the same as B1S2.

The thinking behind this is this. B1 == Bank 1. S2 == Sensor 2. In these trucks, you will not see any other Bank 2 (B2) sensors other than B2S1. The rest are Bank 1 sensors. One would think that GM would have made this change in 98 when they dropped the downstream pre-cat O2 sensor (which was for emissions monitoring only), but they did not. It was not until the PCM change that corresponded with the MFI engine that they made that change. From 98 thru mid-02, the B1S2 and B1S3 sensors were one in the same physical part in location and wiring.

 

Wow thank you! Now I know exactly what to look for!

I really appreciate all your advice and help!

Thanks!