18B Vacuum Supply From Back Pressure Valve to EGR

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 2,000 RPM.
3. If vacuum gauge reading is near the same as previously taken during step A, proceed to step C. 18C Checking EGR Valve Operation
4. If vacuum gauge reading is not near the same as previously taken during step A, replace EGR/back pressure valve assembly.