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Home >> Mitsubishi >> 2002 >> Lancer ES, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0401: EGR Flow Insufficient Detected >> Diagnostic Procedure
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Diagnostic Procedure

CAUTION: To prevent damage to scan tool, always turn ignition switch to LOCK position before connecting or disconnecting scan tool.
  1. Check the EGR system. If there are no abnormalities, go to next step. If there are any abnormalities, repair as necessary. After repairs, go to step  3 .
  2. Using scan tool, check manifold differential pressure sensor. Connect scan tool to data link connector. Start engine and run at idle. Set scan tool to the data reading mode for data list item 95: MANIFOLD DIFFERENTIAL PRESSURE SENSOR. Warm up the engine to normal operating temperature. Data should be 64-78 kPa with engine idling. Turn ignition switch to LOCK position. If the sensor is operating properly, clean the EGR valve and EGR passage. Then go to next step. If the sensor is not operating properly, go to DTC P1400: MANIFOLD DIFFERENTIAL PRESSURE SENSOR CIRCUIT MALFUNCTION  .
  3. Test the OBD-II drive cycle. Carry out a test drive with the drive cycle pattern. See EGR MONITOR  under VERIFYING REPAIRS. Check for DTCs. If DTC P0401 is output, repeat diagnosis. If DTC P0401 is not output, inspection is complete.
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