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Home >> Mitsubishi >> 1995 >> Eclipse GSX, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes - 2.0L Turbo >> Diagnostic Tests >> Code P0400: EGR Flow Fault
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Code P0400: EGR Flow Fault

NOTE: For component terminal identification, see TERMINAL IDENTIFICATION  in this article. For appropriate WIRING DIAGRAMS, see WIRING DIAGRAMS  section.
  1. Install "T" fitting between Green-striped vacuum hose and EGR solenoid nipple. Connect hand vacuum pump to "T" fitting. Start engine. Monitor vacuum while racing engine. If coolant temperature is 68°F (20°C) or less, vacuum should not exist. If coolant temperature is 176°F (80°C) or more, vacuum should momentarily rise over 3.9 in. Hg.
  2. If vacuum is as specified, go to step  5 . If vacuum is not as specified, disconnect White-stripe EGR vacuum hose from throttle body nipple. Connect hand vacuum pump to nipple. Start engine and gradually increase RPM. Vacuum reading should remain constant as RPM increases. If vacuum is as specified go to next step. If no vacuum exists, check throttle body purge port.
  3. Turn engine off. Label and disconnect both vacuum hoses from solenoid valve. Disconnect electrical connector. Connect hand vacuum pump to solenoid valve nipple where White-striped hose was connected. Apply vacuum to solenoid valve. Vacuum should hold.
  4. Apply battery voltage to terminals of solenoid valve. Vacuum should bleed down when voltage is applied to terminals. Using an ohmmeter, check resistance across solenoid valve terminals. If resistance is 36-44 ohms at 68°F (20°C), go to next step. If resistance is not 36-44 ohms at 68°F (20°C), replace valve.
  5. Disconnect "T" fitting and connect hand vacuum pump to EGR solenoid nipple. Apply 7.9 in. Hg of vacuum to EGR solenoid. If idle speed does not change, go to step 8). If idle becomes rough or engine stalls, go to next step.
  6. Using scan tool, read SERVICE DATA No. 95 (manifold differential pressure sensor). Scan tool reading should be 800-2400 millivolts at idle. Reading should temporarily increase above 800-2400 millivolts when throttle is opened quickly.
  7. If scan tool reading is within specification, go to next step. If scan tool reading is not within specification, check manifold differential pressure circuit. See CODE P1400: MDP SENSOR CIRCUIT FAULT  .
  8. Remove EGR valve and check for sticking or obstructions. Apply 20 in. Hg of vacuum to EGR valve. Vacuum should hold. Check that EGR valve remains closed with 1.6 in. Hg or less of vacuum applied. Check that EGR valve is full open with 7.9 in. Hg or more of vacuum applied.
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