AIR33 - Check Air Flow at Check Valve
Vacuum Check Valve:
^ Key OFF.
^ Remove check valve from vacuum lines (note which direction check valve is installed).
^ Connect auxiliary vacuum source to black side of check valve.
^ Connect vacuum gauge to opposite side of check valve.
^ Apply 54 kPa (16 in Hg) vacuum to black side.
^ Does gauge indicate 54 kPa (16 in Hg)?
YES -- Go to AIR34. AIR34 - Verify Check Valve's Ability to Hold Vacuum
NO -- Replace check valve. Verify drive concern.