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Home >> Mazda >> 2001 >> MX-5 Miata Base, Standard >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Self-Diagnostics >> Diagnostic Tests >> DTC P0402: EGR System, Excessive Flow >> Diagnosis & Repair Procedure
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Diagnosis & Repair Procedure

  1. Ensure FREEZE FRAME DATA has been recorded. Check for related service bulletins. Repair as necessary and go to next step.
  2. Turn ignition off and on. Using scan tool, check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTCs are present, go to appropriate test. If no other DTCs are present, go to next step.
  3. Turn ignition off. Remove EGR valve. If EGR valve base gasket is okay, go to next step. If EGR valve base gasket is damaged or missing, replace gasket and go to next step.
  4. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Perform PCM adaptive memory drive mode. See DRIVE MODES  under SELF-DIAGNOSTIC SYSTEM. Using scan tool, access RFC FLAG PID data. If PID data is ON, go to next step. If PID data is OFF, repeat this step.
  5. Perform EGR monitor repair verification drive mode. See DRIVE MODES  under SELF-DIAGNOSTIC SYSTEM. Access ON BOARD SYSTEM READINESS TEST menu of GENERIC OBD II FUNCTION and check DRIVE MODE completion status. If EGR system monitor is compete, go to next step. If EGR system monitor is not complete, repeat this step.
  6. Reconnect all connectors. Using scan tool, check DIAGNOSTIC MONITORING TEST RESULTS. If TEST No. 10:41:00 is within specification, go to next step. If TEST No. 10:41:00 is out of specification, replace PCM and go to next step.
  7. Cycle ignition from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If any other DTC is present, go to appropriate test.
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