Vacuum Control
Connect Vacuum Tester (116 589 25 21 00) with "Y" fitting to EGR valve. Check vacuum values and position of vacuum control flap. Vacuum values should be 0 in. Hg at 750 RPM; 4-9 in. Hg at 1200 RPM, and 0 in. Hg at 3000 RPM. If vacuum test values are okay, go to next test. If vacuum test values are not okay, check vacuum supply and individual components.