Oxygen Sensor

My 95 neon's check engine light came on the other day while driving around town. Alledgedly the oxygen sensor is the source of the problem but the performance has not changed any as I would have expected it to. Anyway, i have no idea where its located on this car. Can anyone help?

there are 2.
upstream and a downstream.
upstream is near the exhaust manifold
downstream is on the pipe after the catalytic converter.
:)

heres my question:
i have the same problem, light came on O2 sensor is bad.
ODB code (dash code 21) reader code P0134, anyone know which sensor this code is refering to? up or down?

Your performance may not be affected now, but it could be in the long run. I don't know how to test which one is the bad one. So when my codes came up for it I just replaced both, figuring if one goes, the other would soon follow :p

Neons are famous for blowing sensors in general.....at least mine is anyway :lol2:

Same thing, when my car read a code 21 I replaced both. If one goes the other isn't far behind. But if you have a budget problem there is a way to tell which one is bad, but its a pain. Tell me if you don't want to replace both and I will detail the procedure.

i thought how u were supposed to test if an oxygen sensor was bad was to hook up the "heater elements" of the 4 ports of the Oxygen Sensor connector to an ohm meter and if its between like 5 and 7 your good. i tried doing that with mine a little bit ago and the prongs for the omg meter couldnt fit in the ports. and i also have no clue what the "heater elements" are. all i know is that theres 4 wires, 2 white, 1 grey, 1 black.
what i did for the ohm meter was get normal wires and plug em into the sensor and hook the other end to the ohm meter...that didnt work to well, so if someone knows how to REALLY test a Oxygen Sensor, please...do tell
thanks

The Haynes manual tell you the process by which you test the sensors, so look there. Maybe you will be lucky enough to check it out at the store and not have to buy one, or maybe you can get one cheap on eBay. I think you should go ahead and buy one, but that's just me. ;)

To get your probes in the connectors, grab a couple pieces of wire to fit in the connectors and make the circuit for you. Good luck.

just wanted to say just because your car gives you a o2 code doesnt mean its bad...

i tohugh mine was bad...i had gotten the code for it...after i tried to get it out to test (i couldnt, it was stuck pretty good) i decided to go ahead and check out the rest of the car....we had been having some idle and misfire problems...turns out the spark plug gaps were WAY off...suppose to be 0.035 and they were all in the 0.048 range...hmmm.

well i regapped the plugs and all the codes and problems went away.

turns out the o2 is just fine.

(a little late with my reply)

but thats what it was....the plugs

the gap was WAY off...

thanks for your help