02 sensor test

If I remember right, years ago I read that they did not make a tester that could test the oxy
sensor without rendering it useless. That testers were not sensitive enough and would blow it. Can any one confirm or dispute this. I know technology has come a long way in 10 yrs.
Is there a way to test the oxy sensor? Thanks for any input.

Apparently this was a dumb quesion or no-one knows the answer. Do you just replace it and hope that was the problem?

Most O2 sensors can be tested on the vehicle using a digital volt/ohm meter. Connect the positive lead to the sensor out put lead--the one going to the ECM--set the meter to the lowest DC volt scale that will read a full volt. Run the engine until operating temp is reached. You should see ~.3v to .9v, rapidly changing, going below and above .45v so quickly that it's hard to say what the voltage is, other than the lows and highs it is reaching. This is an overall test that indicates your probably in closed loop and the ECM is responding to changes in "O2" sensed by the O2 sensor; a slow changing sensor, or one that stays below or above .45vdc indicates a problem. You can also check the O2 sensor by removing it from the engine, and mounting it in a vise. Then connect the digital VOM to the out put lead and sensor case(ground). Using a propane torch, heat the O2 element while observing the VOM. The out put should attain ~.9 to 1volt fairly quickly. The next test is to remove the heat and observe how quickly the out put drops to near 0vdc. A slow drop indicates a "lazy" sensor that should be replaced. On models with built in heaters (3 and/or 4 wire sensors), you can check the heater windings using the ohm meter function of your DVOM; your basically looking for continuity, indicating the heater windings are OK.
Google for info on O2 testing. There a number of very good "how to" articles on testing sensors.

Thanks XJBubba, That was a very informative

write up. My 93xj has 3 wire connectors on the

TPS and CPS but I have not checked to 02 wires

yet, My 00xj has never given me a problem, I

just believe in being prepared when problems

arise. I will Google and see if I can come up

with some wiring diagrams that will tell how to

identify which wires are input, output and

ground. Thanks much XJBubba