I have a 2000 Dodge Caravan that we just got and attempting to smog test. Check engine light came on early last week. We used our OBII reader to see it had P0135, then P0134. We replaced upstream oxygen sensor and the light went away. After driving about a day and half, the light came back on. We checked the code again and it was P0135 again. We cleared it, thinking maybe it's still stored in computer's memory (we didn't pull the battery or clear it after we replaced the sensor). This morning it came back on. The strange part is that it hasn't come back on while driving. It only seems to come on when I start the car and then it just stays on. Any thoughts?

 

failed trip monitor test. MIL comes on if vehicle off tests fail.

 

my Stratus would do that(no light while running, but comes on when starting) mine ended up being the O2 sensor.... maybe they put a bad one in or the connector is loose or wiring problem...

 

Thanks for the replies. I had a couple of mechanics look at everything to be sure we put it in right and they tested it out and came to the same conclusion...we got a faulty O2 sensor. My husband went through three starters in a row for our Maxima with this store and we were hesitant to buy the O2 sensor from them. Well, we probably shouldn't have. I'm exchanging (if I can't get a refund) today and getting a new one and see how that one works out.