• New to posting, but love to read other posts almost daily. We have a 1989 245dl wagon which needs to pass the emission test in order to hit the road. As they would say in the years pass, i'm somewhat of an old school (shade tree mechanic), things like change the oil, rotate the tires etc. Now i'm dealing with getting this Volvo wagon ready to pass an emission test. It fail on its first attempt and I think its the Oxygen Sensor (Lambda Sensor) which i have posted and also its has never been attached to a attachment or connection, if im right, is this the Oxygen Sensor and could the second photo be it's connnection, because that's the only open connection in the engine compartment.
  
  Could this be my Oxygen Sensor (Lambda Probe)?
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  This is the only open connection in the engine compartment.
  
  End shot of the connection.
  

 

The open female connection you show is to be able to connect a remote starter switch to. You can use that to easily bump the engine around when you are adjusting valves or for other reasons.

The O2 sensor screws into the back of the exhaust manifold above where you have photographed. Why do you think it is bad? Has your car failed an E test? If so what are the readings? How did it fail? (too much of what gas?) Are there any self diagnostic codes stored? It gets expensive doing the guess, buy, replace and repeat method of car repair - I don't suggest that method.

And sorry it's clear that if you have no clue what an O2 sensor is - you should not be replacing it on a guess or otherwise.

What is most prominent in your first photo is the EGR pipe. That sends exhaust gasses around to the EGR valve under the intake manifold that opens under certain conditions, diluting the intake charge and reducing the heat of combustion, which reduces nitrous oxides. (NO2) Whatever you do don't try to loosen or remove that pipe unless absolutely needed. It will be rusted together and will break when that is attempted. There are easy (non destructive) ways to test the ERG system if needed.