Can I Replace an O2 Sensor?

courtesy of Bob, The Auto Answer Man

Hi Bob,
I have been driving my 94 Caravan for about a year with the check engine light coming on intermittently. The car generally runs fine, but I have felt some hesitation once in a while. Thinking the fuel injectors are dirty, every few weeks, I put in a can of cleaner. I know it's probably a waste of money, but I am a poor geologist and don't really want to bring the car in for service since it'll be $500 dollars minimum!

I checked the error codes and get what I believe to be 12, 21, 55. In checking, it looks like 21 means the O2 sensor has failed, and with gas prices so high, I want to fix it. Can I do it myself?
Jeff in Portland, OR

If you can get to the rear spark plugs on that motor, then you can change the oxygen sensor. It basically just screws into the exhaust pipe somewhere between the engine and the catalytic converter (some cars also have an extra one after the catalyst as well). You will need a special 7/8" socket made for oxygen sensors or a very long 7/8" wrench. Simply unplug the wiring connector and unscrew the old oxygen sensor. Then, screw in the new, making sure it's tight, as you don't want it to leak. Plug in the wiring connector. Make sure that the threads of the new sensor have some anti-seize on them. Most come already coated.
Good Luck!
Drive Safely!
Bob, The Auto Answer Man

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