Pressure Operated Electric Divert/Electric Switching (PEDES)

Pressure Operated Electric Divert/Electric Switching (PEDES) valve:

This valve, Fig. 17, is ECM operated similarly to the ED/ES type, but uses air pump pressure rather than intake manifold vacuum to operate control valves. Air pump pressure builds up against a control valve which is operated by the ECM through 2 solenoids.
When engine is cold (``Open Loop''), the port solenoid is energized and air pump pressure opens the passage to the exhaust ports. During normal operation (``Closed Loop''), the port solenoid is de-energized, the converter solenoid is energized, and air pump pressure opens the passage to the catalytic converter. When the ECM determines that air divert is necessary, both solenoids are de-energized and air pump output is diverted to the air cleaner through a divert/relief valve. The divert/relief valve limits system pressure.