Volvo: air pump and sensor, tail pipe, warning light

Question
QUESTION: Hi,

A warning light comes on related to fuel emmissions and I've been told by my volvo garage I need a new air pump and relay.  They are quoting £350 plus labour which is too steep.  Do you know the exact name of the parts so that I can get second hand parts fitted and do you know roughly how much this would cost?

many thanks
Norrie

ANSWER: Norrie,
I do not know the year and model of your car. However if your are referring to the SAS pump and it's relay, I would not go with a used one. That pump tends to have condensation that settles in it and causes the pump to lock up. They are not reliable as used parts.
If you still want a used unit SAS (secondary air system) pump and relay. I would recommend that you also replace the SAS check valve. Most times that is the cause of moisture and is also affected by moisture in the system.

---------- FOLLOW-UP ----------

QUESTION: Many thanks for your quick response.  Most impressed.
The model is an 850 and year is 1995.  Apologies for my ignorance and lack of detail but the air pump relates to emmissions and apparently doesn't affect the running of the car.  Is this the one you are talking about?  I'm told it might fail the MOT if I don't replace it?  Is this correct?  
thanks
Norrie

Answer
Norrie,
That is the pump that I referred to yes. It may fail the MOT all you could do is try to see if it passes. Most times on the pre 96 cars they sample from the tail pipe and that (the SAS) has no effect on the tail pipe. So you may want to try and see what happens. Where is it you are located?