There's a few different components to this system...an electric pump, a mechanical valve, a vacuum solenoid, the piping, and the pre-cat O2. The purpose of the system is to heat up the catalytic convertor on start up. Check the fuse, the vacuum lines, and activation of the mechanical valve using a hand vacuum pump. You want to make sure the valve opens and closes as well that the solenoid clicks when supplied power and ground.