AIR code can be tricky..the check is to make sure the pump runs and that the sov is allowing vac supply to the valve so the air can get pumped into the exhaust ports . If that is working,then you want to check the 02 sensor to see if it is still capable of a lean reading. That is how the ecu determines if the AIR system is working..it does a self test and looks at the 02 sens value to go real lean. A weak sensor that is not capable of a very low [lean] voltage will pop an AIR code even though the AIR system is working correctly.
The ecu electrical sig for the AIR sov is in parallel with the pump clutch, so if the pump is working, you know you have a sig to the sov.