Evaporative Emissions System: Testing and Inspection

Tank Pressure Control Valve:

FUNCTIONAL TEST
Valve Diaphragm Check
With a hand vacuum pump, apply approximately 51 kPa (15 in Hg) to the Evaporative Emission Pressure Control Valve vacuum tube. After ten seconds, there should be at least 17 kPa (5 in Hg) vacuum remaining. Be sure the hand vacuum pump being used does not have an internal leak and the hose connections to control vacuum tube and pump are secure. If after 10 seconds there is less than 17 kPa (5 in Hg) vacuum, the valve must be replaced.

Valve Flow Check
With 51 kPa (15 in Hg) vacuum still applied to the control vacuum tube, attach a short piece of hose to the valve's tank tube side. Blow into the tube. You should feel the air pass through the valve. If air does not pass through, the valve must be replaced.