O2 sensor troubleshooting 1998 Caravan

Discussion in 'General Motoring' started by geo.nova, Jan 24, 2009.

  1. geo.nova

    geo.nova Guest

    1998 Caravan 3.0L
    replaced downstream o2 sensor about three months ago
    check engine light went off-good
    replaced upstream o2 sensor last week
    check engine light came back on saying downstream o2 sensor faulty???

    Anyone now if this could be something else. I don't think I should
    have to replace o2 sensor after only three months.
    Is this really going to effect anything if I drive with light on. I
    don't have the time or money to deal with this kind of crap. Nobody
    has been able to offer an answer on this so far.
    What about disconnecting completely? Could this harm the engine in any
    way? How much could it actually effect gas mileage?

    Thank in advance.
    geo.nova, Jan 24, 2009
  2. geo.nova

    Bill Putney Guest

    My guess is that you replaced them with Bosch sensors. Bosch sensors do
    not work well on some (many? all?) Chrysler products. Daniel Stern used
    to say this, and I was skeptical, but I have seen thread after thread
    after thread on the various LH car forums by people who learned the hard
    way attesting to the fact that it is true. Get them from the dealer.
    Also NGK's work well (I think for some years they are the OEM sensor).
    Bill Putney, Jan 24, 2009
  3. what kind of o2 sensors did you use??
    a good scan tool tool is the quickest way to look at operating voltages
    but a d.v.o.m will work but takes more time to hook up
    i can only hope you used chrysler parts and not autozone crap
    man of machines, Jan 25, 2009
  4. geo.nova

    bllsht Guest

    Must be a new trouble code. I've never seen a code that says an O2
    sensor is faulty.
    The answer is it needs to be properly diagnosed.

    Can't help with the money, but, if you used the time you've spent
    whining about it and throwing parts at it, on actually diagnosing it
    instead, you'd be better off.
    Disconnecting it will guarantee the light will always be on. Then
    you'll never know if something worse has developed.

    In addition to monitoring cat condition, the downstream O2 is also
    used as an input by the PCM to determine upstream O2 goal voltage.
    Fuel mileage may be a concern, but I'd be more concerned about what
    would happen to the cat if it ended up running too lean.
    bllsht, Jan 26, 2009
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