Thanks. I had it cleared and it came back on within 24 hrs. I will keep driving and hoping for the best. If its still on this weekend I guess we will try disconnecting the battery for an extended period of time.

 

I'm sorry lady. The thread title says P0155, you said you changed the part.

Which of those did you change? If the code was 155 it should have been '3'

If that was all correct then it isnt unusual for wires in that area to be damaged by the heat of the cat.

And BTW, guys.. it's a heater circuit failure

 

omg! My son advises that according to your diagram it was #1 that was changed. So, do we leave the sensor that was changed in and get the same sensor for the #3 on this diagram. I'm sorry for the trouble but greatly appreciate the assistance.

 

I just replaced both oxygen sensors in my 04 with AC Delco ones from the dealer because I previously tried using after market ones from Auto Zone (Bosch) and after the codes were cleared the light always came back on. Just figured I'd give you the heads up because for some reason Blazers are known to have trouble with after market O2 sensors and ever since I replaced with AC Delco, I haven't had a problem. You'll be paying almost double for the AC Delco's roughly $120 a piece compared to $67 for Bosch but you can say goodbye to the engine light. Hope this helps. Goodluck!

 

Easy mistake... sort of hidden unless you know to look for it.

If you didnt damage the one you took out, just install it. Assuming you havent had a lot of problems, the post-cat O2 doesnt get the same amount of contamination and wear and tear.

 

your a lifesaver, thank you kindly! The old one that came off looks bad, so should we keep that new sensor in and jut get another like it for the bank 2 sensor 1? or put the cruddy one back on and use the new one for the right area?

 

Beats me how Bosch, the people that made them common on production cars have trouble matching them.

Delphi sensors... the ones came on it are 35 bucks on rockauto.com. AC Delco's are 47 bucks.

PS ,... doesnt matter what it looks like on the outside, as long as the wires are intact. But cant hurt to change it.

Oh... a little footnote: Ac Delco is an AFTERMARKET supplier. They dont even make their spark plugs, NGK does. Lord knows who makes stuff for Delphi but it's the Mfg and QC specs that count.

 

ok...i am seeing upstream and downstream when I am looking for prices. what is the correct for the bank 1 sensor 3 & bank 2 sensor 1? the old sensor end has holes, new one is smooth.

 

That's their way of confusing things. For some cars it makes a difference, so if it says
That means it fits all stated. Hover over that and it says something equivalent.

Always look out for EXC and w/o as exceptions
They are the same. Only one make says 'downstream' and that's probably an error. Except you shouldnt buy it, anyway. Like the man said.. GM parts. That's Delphi and Ac DELCO
The ones in it are Delphi. Why it says OE Part, not OE design or equivalent.

Different maker has different designs for the sensor covers

 

can I / should I just put the old one back where it was and put the new one in the correct place? Will that be ok? Thanks again, for all the info.