Volvo RWD 200 Forum

Hi all:

Finally after many hours of work and (5) trips to the state inspection station for emissions testing, I passed. HOW you might ask/

The initial reading for Nox was ~1750, then after complete tune up it came down to ~1250, then after new O2 sensor. cleaing AMM, new cat back exhause the reading came to about 1160, and lastly added a new CAT for a reading of 969 just one point below the max threshold of 970. The old CAT was only 4 years going with 27K on it. The honeycomb was complete and unpluged with normal soot. I still think it was OK

So as for my new issue. The O2 sensor that I replaced was a Bosch with the long harness (3 wire). AS normal procedure when I change an O2 I use a Bosch 13939 (3 wire for $39.99) as all 3 wire sensor heads are the same. I cut the old sensor leads off and use butt connectors to hook it up. It always has worked for me. But a problem has been noted. The check engine light does not come on when the ignition is set in the #2 postion prior to start. I redid the butt connections 3 times figuring that I had one bad splice but noting changed, not light in pre-start. I checked the ECU output module test block for stored errors and got a 1-1-1 aka no stored error codes.

I have not as yet checked with my VM to confirm an occilation of v from .1v to .9v

What I did that may have effected this is remove the "service engine" bulb in the instrument panel because I could not reset it. The service engine light is next to the Check engine light. I figured I may have moved it so I replaced the bulb and it still did not illuminate. I am perplexed as this has never happened before and I am concerned that the system is not working as it should be.

Has anyone every had this happen? Can you get a bad O2 sensor out of the box? Should I replace the O2 sensor with the correct lead length harness model $120 vs $40) This O2 sensor is in the CAT and I have not replaced it beofore. I have used the 3 wire Bosch with butt connectors in '91 240's witht the O2 sensor in the head pipe and had no problems. Anyting I should check. relays?, fuses, etc?

Thanks