Oxygen sensors eventually need to be replaced in all vehicles. If your vehicle’s O2 sensor is faulty, chances are there will be signs! Check this list to see if it’s time to replace YOUR vehicle’s oxygen sensors:

  1. Sudden decrease in fuel mileage. A defective O2 sensor will likely cause your air-fuel mixture to be too rich and directly affect your fuel economy.
  2. Flashing check engine light or malfunction indicator lamp in the vehicle?s dash board. Of course this can happen for other reasons as well (and a defective oxygen sensor is one of them!)
  3. Failure to pass smog. According to the EPA (Environmental Protection Agency) and CARP (California Air Resource Board) 50 to 60% of all smog test / emission test related failures are attributed to defective oxygen sensors, causing either low or high CO emissions.
  4. Overall poor vehicle performance; rough idling, stalling, hesitation on acceleration, etc.
  5. And the most accurate diagnosis is achieved using an OBDII code checker. All cars made in 1996 and after are equipped with an OBDII interface. An OBDII code checker identifies defects in the exhaust system of the car. If your oxygen sensor has failed, the code checker will generate a diagnostic trouble code that specifically indicates your oxygen sensor is bad.

Guidelines for replacing the oxygen sensors in your car, courtesy Bosch.com:

  • The unheated 1 or 2 wire O2 sensors, used in vehicles from mid-1970s through early 1990s, replace every 40,000 to 50,000 miles.
  • Heated 3 and 4 wire O2 sensors, used in the vehicles from mid-1980s through mid-1990s, replace every 60,000 to 70,000 miles.
  • Newer vehicles made in mid-1990s and later, replace the oxygen sensors every 100,000 miles.

Conclusion, properly functioning O2 sensors are critical for optimal fuel consumption and good car performance. When in doubt, it is best to replace your faulty oxygen sensor at most, every 100,000 miles.

  • http://pulse.yahoo.com/_6C3WGWXISBYXTPG7NR6LVQ6PDQ Margaret Miller

    A very informative post on oxygen sensor. My car’s oxygen sensor was replaced several times. With these signs, I can now assess whether my car is really having oxygen sensor problems. Thanks!

  • http://www.bes.co.uk plumbing

    These are very helpful notes to remember. I will surely apply this at home.

  • chris

    i recently changed my af sensor and the cel came on again reading the same code prior what do i do now

  • Klhoepsin

    Heated O2 sensors are recyclable…they have a little bit of platinum in them which makes them more valuable than most scrap metal. (they are only worth 50 cents or so) Bring yours to your local repair shop so they can add it to their collection bin – both the technician and the environment will thank you.

  • N00b334

    Have you tried restarting your ecu by disconnecting the positive battery terminal? Then restarting the car and allowing it to idle for ten minutes? I’m not a

  • http://profile.yahoo.com/OXMIE4DITSQWIG2VRI5PPDXQEE John w.

    My 1995 Bonneville stalled and also died when I made left turns. Took it in they said it was the oxygen sensors. It ended up costing me a thousand dollars to get them replaced because they were not accessible. If I had a 1996 Bonneville it would of cost around two hundred.
    Car ran fine afterwards.

  • tamara

    i can be going down hwy and lose power will die and pull over and starts back up sometimes it will shake and not have enough power to accelerat but after a couple of times will start up and run just fine what could be wrong

  • Ashley

    when trying to accelerate the car seems like its not accelerating, was told either the O2 sensor or the wiring to it needs replaced. What will happen if the cars o2 sensor is out? Will it have issues accelerating? like i can accelerate but its not going above 25 to 30 without making it seem like the car is in park and pressing the gas pedal. So I guess what im asking is since the O2 sensor is bad could this be the reason were having acceleration issues…other than that the car runs and drives fine

  • Josh M.

    You got ripped off. I have the same car. The one O2 sensor is behind the engine on the exhaust manifold, not hard to get to at all. I always tell people to ask on forums first and friends/family after.

  • Steve ram

    I replaced my oxygen sensor and my CEL went off but when I used my scan tool it reads yellow an will not pass an emission test, help!

  • Dyler_Turden

    I know this is an old post, but did you resolve it? I believe you have to complete a certain number of drive cycles before the “warning” is removed from the OBC memory…

  • Kathleen

    My kia stalls out when I’m getting gas and them won’t turn over at first. It takes a couple of tries and giving it a little gas to get itto keep from stalling. Could this be my o2 sensor?

  • Chris Smith

    Hi, it could be as easy as a gas cap. Others would be injectors, fuel pump is weak, dirty fuel filter. Did u get a C.E.L.

  • Austyn

    Does not sound like the 02 sensor

  • Austyn

    Does not sound like the 02 sensor

  • Mack

    My truck stalls out and after 5 minutes are so she starts up and then stalls again after a few minutes. I thought I got some bad gas and add some sea foam and it ran good for a short time and then started stalling again. Auto zone tested to see if a code would come up and it did not show any. Can the oxygen sensor be going bad and not show a code? Thanks

  • nathan

    i aint sure its my o2 sensor or not but my 1999 gmc serria runs fine except upon heavy acceleration or when its under a load like going up steep hills ive been told its some type of sensor or its not getting enough gas any ideas

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