EVAP 2-Way Valve Test

Remove fuel filler cap. Remove vapor line from EVAP 2-way valve located above EVAP control canister. Connect vapor line to a "T" fitting from Vacuum/Pressure Gauge (07JAZ-001000B) and Vacuum Pump (A973X-041-XXXXX). See Fig 1 . Apply vacuum slowly and continuously while observing gauge. If vacuum stabilizes momentarily at 0.8-2.1 kPa (6-16 mm Hg, 0.2-0.6 in. Hg), go to next step. If vacuum stabilizes at less than 0.8 kPa (6 mm Hg, 0.2 in. Hg), or greater than 2.1 kPa (16 mm Hg, 0.6 in. Hg), install a new valve and repeat test.
Switch Vacuum/Pressure gauge hose from vacuum to pressure. Slowly pressurize vapor line while observing gauge. If pressure stabilizes momentarily above 1.0 kPa (8 mm Hg, 0.3 in. Hg), valve is okay. If pressure stabilizes below 1.0 kPa (8 mm Hg, 0.3 in. Hg), install new valve and repeat test.

Fig 1: Testing 2-Way Vent Valve Using Vacuum/Pressure Gauge & "T" Fitting
Courtesy of AMERICAN HONDA MOTOR CO., INC.