DR-22B Vacuum From Back Pressure Valve

1. Re-connect EGR back pressure valve vacuum line, then disconnect the EGR valve vacuum line.
2. Connect a vacuum gauge to the disconnected line, then raise engine speed to 2000 RPM.
3. If vacuum gauge reading is near the same as previously taken during step A, proceed to step C.
4. If vacuum gauge reading is not near the same as previously taken during step A, replace EGR/back pressure valve assembly.