AIR34 - Verify Check Valve's Ability to Hold Vacuum

Vacuum Check Valve:

^ Key OFF.

^ Remove auxiliary vacuum source from the check valve.

^ Does vacuum gauge reading remain above 50 kPa (15 in Hg) for 10 seconds?

YES -- Go to diagnosis by symptom to address other possible causes. Diagnosis By Symptom

NO -- Replace check valve. Verify drive concern.