Replacing 2nd O2 sensor on 02 Elantra (vehicles, auto, fuel, exhaust)

[psychofan]

So my 9 years old 2002 Elantra GLS with 99,000 miles had its first "Check Engine Light" come on yesterday. There were no drop in performance, no change in engine noise, no black smoke, etc. Nothing appeared to be wrong except for the darn CEL display. Anyway, went to my local Advance Auto Parts store to borrow their diagnostic tool to find out what the issue may be.

According to the complete diagnosis, O2 sensors actually indicated that they were functioning fine, but I still got the following output:

P0139 MOD$11
Oxygen Sensor Circuit Slow Response
Bank 1 Sensor 2

In any case, I went ahead and deleted the code just to see if it'll come back or if this was some strange random fluke event.

For those of you DIYers who have changed your own O2 sensors, if I was to do this myself, will I need to have any special tools? Bear in mind, I'm a complete newbie, but would like to be more mechanically proficient. From the DIY videos (of other vehicles) that I have seen online, it seems like it's a pretty straightforward job. Basically unplug the electrical connection, then unscrew the old sensor with a simply wrench. Is it that simple on the 02 Elantra as well? Any suggestions on where (or specific brand) I should order a replacement?

Also, are the rear and front O2 sensors interchangeable (i.e. same thing)? I found an OEM replacement on ebay at 01-06 Hyundai Elantra Oxygen Sensor O2 03-06 Tiburon FR | eBay, but it does not say if it's for "Sensor 1" or "Sensor 2."

Thanks!

[JGC97]

If you're driving mainly around town, take it out on the freeway and "blow the carbon out," as my dad used to say. It worked for me. About ten years ago, I had the O2 sensor changed because the "check engine" light came on. But when it happened again little over a year ago, I just got on the freeway and drove! The light stayed on until I shut the engine off but when I started it up again, it was off. Try it. What's the harm? If it's broken, how much worse could you make it?

[Egobop]

The 1 and 2 sensors are not interchangeable. You have to buy the correct one. The wire connectors are USUALLY different on the different sensors so that you can't accidentally hook the wrong sensor up. They sell special sockets for oxygen sensors that are not expensive and are readily available at auto parts stores. When I change oxygen sensors I tend to run the car to operating temperature to heat up the exhaust so that it is easier to remove the sensor. If doing this be careful since the exhaust and the sensor will be HOT.

[piyf]

Pretty easy job. Just use a wrench and use a lot of force to get it off. And I don't know about all cars but typically the front and rear O2's are not interchangeable. The one you need to replace is the one that is after the catalytic converter. Which does only one thing and that is to see if the catalytic converter is working.

[piyf]

Originally Posted by HereOnMars

If you're driving mainly around town, take it out on the freeway and "blow the carbon out," as my dad used to say. It worked for me. About ten years ago, I had the O2 sensor changed because the "check engine" light came on. But when it happened again little over a year ago, I just got on the freeway and drove! The light stayed on until I shut the engine off but when I started it up again, it was off. Try it. What's the harm? If it's broken, how much worse could you make it?

If it's the front O2 you could cause major damage to the engine. If it's not reading the proper air fuel mixture and you floor it, it could go boom.

[JGC97]

Originally Posted by danieloneil01

If it's the front O2 you could cause major damage to the engine. If it's not reading the proper air fuel mixture and you floor it, it could go boom.

I'm sure it could. I simply related a story of what happened with my car. Going forward, I'll have to put a disclaimer below my comments that reads: Don't try this at home."