Herb,

Thanks for the information. I really believe there is some other problem causing the air pump relay not to activate. When the CHECK ENGINE light originally came on, I had the dealer check the codes. They found two air pump related codes and wanted to replace the pump, valve, etc.

I did some checking on my own and found the pump was OK, I removed it and looked inside. There were absolutely no signs of moisture invasion.

Also,I've checked the the system several times when the car is cold and everytime the controller valve opens and activates the check valve. When this happens, I can feel exhuast pulsing back through the air pump inlet hose because the pump is not running. This can't be normal because allowing the check valve to open when the pump is off would eventually cause the same problem as a stuck check valve. It seems that the air pump should run whenever the check valve is open. That's why I'm stumped.