Hello all, I have a 2002 Blazer 4.3 4x4. I got a PO155 DTC a few days ago and reset the light.
CEL came back on today so I think I need to replace the O2 sensor (bank 2 sensor1).I'm look for
part number and suggestions on where to purchase it. Or is this a dealer item?Any help in this matter
would be appreciated.
Thanks Jim

 

Not sure which one you need, Autozone lists them as...
Bosch
After cat-52.99
B4 cat-73.99

Denso
65 for the universal... ???
and 103 for the OEM.

 

Thanks Mike, Under the tech articles it only suggests one sensor behind cat. convener. This is my first Blazer
I'll check Autozone.Thanks

 

DO NOT buy a Bosch unless you like paying for it again. AC Delco #213-802 (OE#12559850)! RockAuto.com has them for $84.89 or see if you have an AC Delco retailer close by checking out their website.

P0155 Explained - Heated Oxygen Sensor Heater Circuit (bank 2, sensor 1)

The first thing I would do is swap the pre-cat sensors side to side. The B2S1 sensor is the sensor directly ahead of where the "Y" in the y-pipe is on the passenger side. The B1S1 is on the driver side just behind the exhaust manifold. Swap them side to side and see if the code changes to B1S1 (P0135). If it does, then there is a problem with that sensor and it needs to be replaced. If it does not, then you may have wiring damage or some other problem with the circuit.

 

Thanks for the info,I'll do the swap and clear the code.

 

Kyle, After the swap of the two o2 sensors i got code P0135. Looks like a bad sensor,
I'm going to get the AC Delco. I don't know when it had a tune-up last so I'm going to
do that next.I just got this Blazer 83000 miles on it now. I think it had the original air filter
it was pretty bad.
Thank for your help. Jim

 

Sounds good. Always great when a plan comes together and the appropriate component is proved to be the problem. Would suck to spend $80+ only to find out there was a wiring problem.

 

What about is the code still the same, no change and now my truck is getting problems to start. What can it be?

 

Huh??? Do you have a question that is not answered in the link I posted above?

 

Yes swartlkk I asked what about if after I done all the steps you mention before I still get the same P0155 code? I did a tune up, gas filter,and swap the O2 sensors side to side and nothing change. Also someone told me there is more than 2 O2 in my Extreme is that correct? how can I do wiring change or determine if there is a problem with the circuit?Thanks again!!!