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General System Inspection

  1. Visually inspect all EGR components, vacuum lines and wiring for opens, bad connections or damage. Repair as necessary.
  2. Start engine. With engine cold, place finger against EGR valve diaphragm. Increase engine RPM. Diaphragm should not move. If diaphragm moves, inspect No. 1 EGR vacuum solenoid valve and coolant temperature switch for proper operation.
  3. After vehicle has reached operating temperature, repeat test. Diaphragm should now move.
  4. If diaphragm does not move and no change in engine performance is noted, remove EGR vacuum line and apply 6 in. Hg using a hand-held vacuum pump. If engine runs rough, go to step 6).
  5. If RPM does not change and engine does not run roughly or stall, remove EGR valve and inspect EGR passages for carbon build-up. If passageways to intake and exhaust system are clear, replace EGR valve.
  6. If engine runs roughly in step 4), inspect vacuum solenoid valves and modulator valve for proper operation.
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