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EGR System

  1. Connect Vacuum Tester (201 589 13 21 00) with "Y" fitting to EGR valve. With engine idling at 850-950 RPM with approximately 300 mbar, briefly apply full throttle. Vacuum should decrease. If vacuum decreases, go to next step. If vacuum does not decrease, go to step 3).
  2. Connect vacuum tester directly to EGR valve. Turn engine off. Apply 300 mbar vacuum to EGR valve. Pull off vacuum line. EGR should close audibly. If EGR closes audibly, EGR system is functioning properly. If EGR valve does not close audibly, replace EGR valve.
  3. Repair or replace EGR valve vacuum transducer as necessary. Mechanically check airflow sensor, vacuum line connections, and EGR valve microswitch. Check Electronic Diesel System (EDS) control unit connector and coolant temperature sensor. Repair as necessary.
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