LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mitsubishi >> 2001 >> Eclipse GS, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0401: EGR Insufficient Flow Detected >> Diagnostic Procedure
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Diagnostic Procedure

  1. Check EGR system. See EXHAUST GAS RECIRCULATION (EGR) under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING article. If problem exists, repair as necessary and go to step  3 . If problem does not exist, go to next step.
  2. Start engine and let idle. Using scan tool, check data list item No. 95 (manifold differential pressure sensor). With engine idling, pressure should read 62-76 kPa (2.4L) or 22.6-36.0 kPa (3.0L). If pressure is as specified, clean EGR valve and EGR passage, then go to next step. If pressure is not as specified, check manifold differential pressure sensor circuit malfunction. See DTC P1400: MANIFOLD DIFFERENTIAL PRESSURE (MDP) SENSOR CIRCUIT MALFUNCTION  .
  3. Test drive vehicle following OBD-II drive cycle EGR monitor pattern. See EGR MONITOR  under OBD-II DRIVE CYCLES under VERIFYING REPAIRS. Check for DTCs. If DTC P0401 is output, retry diagnostic procedure. If DTC P0401 is not output, inspection is complete.
scientia non olet · About LEMON Manuals