I am still having problems getting the air pump to come on when it is supposed to. Here is an update on my findings so far:
1. The pump runs fine and will come on if I remove the relay and jumper the power terminals.
2. The SAS controller workes fine. I connected a vacuum gauge to the SAS vacuum supply line and started the engine (engine cold). Vacuum was present for about two minutes and then it was cut off.
3. During the warm up period, I had a voltmeter connected to the power supply lead for the air pump, reading was 0 volts.
4. With the ignition in position II, I read 12.5 volts at the air pump supply terminals in the relay box. I read 9 volts at the solenoid terminals in the relay box.
5. With the engine running and warmed up, I read 14 volts at the power terminals and 10.8 volts at the solenoid terminals.
6. I replaced the airpump relay and still no luck.
NOTE: If the airpump relay is removed, the CHECK ENGINE light will come on soon after the engine is started. With the CHECK ENGINE light on there is no voltage present at the air pump terminals in the relay box.

It seems to me that if the ECU controls the air pump relay, the problem may be in the ECU. All other components appear to be functioning properly. Is there any test which would confirm a faulty ECU? The ECU is covered under the extended warranty for certain emissions control components and it would be nice to have Volvo foot the bill for this problem.

My dealer diagnosed this as the typical SAS valve/ air pump failure and wanted to replace those components to the tune of $550.

I would greatly appreciate any additional assistance on this situation as the dealer has not been receptive to my telling them they misdiagnosed the problem.
(Thanks Rich K. at Bay13 for your help so far.)