Originally Posted by liberalswine
Okay I had the same issue last night. Except, in addition to the pump being stuck on, the plastic tube on my was melted. I have no clue what would cause it to heat up like that since nothing in its environment would cause it except for the unit itself. Any suggestions? Here's a picture of where it was melted.
The AIR pump pumps air from the air intake into the exhaust to help heat up the primary catalyst. There should be a one way valve to prevent exhaust from going backwards into your intake. If that failed, or is leaking, you could have exhaust going up to the pump and possibly melted that hose. That's pure speculation, as I have no idea where exactly that is from that pic, and I don't have an AIR equipped car.