Your Vehicle: 2001 Ford Escort ZX2 L4-2.0L DOHC VIN 3
 
Vehicle » Powertrain Management » Emission Control Systems » Vacuum Check Valve » Description and Operation  
 
 
  Description and Operation  
 

VACUUM CHECK VALVES

Vacuum Check Valve
  

A vacuum check valve (Figure 125) blocks air flow in one direction. It allows free air flow in the other direction. The check side of this valve will hold the highest vacuum registered on the vacuum side.