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 are: At 750 RPM, 0 in. Hg; At 1200 RPM, 4-9 in. Hg; At 3000 RPM, 0 in. Hg. If vacuum test values are OK, go to next test. If vacuum test values are not OK, check vacuum supply and individual components.