O2 sensor troubleshooting 1998 Caravan

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. K
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
snipped-for-privacy@hotmail.com wrote:

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
(To reply by e-mail, replace the last letter of the alphabet in my
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
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
snipped-for-privacy@hotmail.com wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sat, 24 Jan 2009 06:54:33 -0800 (PST), snipped-for-privacy@hotmail.com wrote:

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.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.