I've had a "service engine soon" light for about a week. I recently got gas at a new station and thought maybe the gas was bad, so waited until I ran about a tank of the gas I usually get before grabbing the code.

Where is that O2 sensor located?

 

This may help you out a bit if you have a 95 or 96 blazer, if not this question has been answered quite a few times just do a quick search.
But, more information on your vehicle would be helpful.

 

the year and other info would be helpful to start out with.

 

Yes, please include your vehicle information in your posts requesting help. From your other posts, I see that you have a 2004.

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

The B2S1 sensor is between exhaust manifold and the 'y' in the y-pipe on the right side of the engine (looking at it from the driver seat).

 

Yep a 2004, I forgot to post that info.

Thx for the help guys. I'll have a look at it in the next couple days and see if it is the wires. If not I'll replace it and let everyone know the outcome.

 

Good luck with it.

 

I looked at the wires and they look OK.

I don't have a wrench to fit the O2 sensor, so I'm gonna' have someone fix it for me.

BTW, what do you figure it should cost to have the sensor replaced? How 'bout the cost of a sensor?

 

not sure on price depends where you live most mom and pop shops where I live are around $60 a hour.

As for the sensor just look it up on orilies website or something.