LEMON Manuals: Even more car manuals for everyone
Home >> Mazda >> 2003 >> Tribute LX, 4WD >> Repair and Diagnosis >> External Pages >> Different car >> Section 26 (Engine Controls - Self-Diagnostics) >> Diagnostic Tests >> DTC P0401: EGR System, Insufficient Flow >> Diagnosis & Repair Procedure

Diagnosis & Repair Procedure

WARNING: This page is about a different car, the 2002 Mazda Protege5 and 2002 Mazda Protege. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition off. Connect scan tool to DLC-2. Turn ignition on, engine off. Monitor for FREEZE FRAME DATA and ensure data has been recorded. Check service bulletins for repair information related to this DTC. If repair information is not available, go to next step. If repair information is available, perform diagnosis and repair as necessary. After repair, go to step  8.
  2. Turn ignition switch off and then start engine. 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. Check for vacuum clogging, restrictions or leaks. If no problems are present, go to next step. If any vacuum clogging, restrictions or leaks are present, diagnose and repair as necessary. After repair, go to step  8.
  4. Check EGR valve operation. See EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING – MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 article. If EGR valve is operating properly, go to next step. If EGR valve is not operating properly, replace EGR valve. After repair, go to step  8.
  5. Check EGR boost sensor operation. See EXHAUST GAS RECIRCULATION SYSTEM under EMISSION SYSTEMS & SUB-SYSTEMS in SYSTEM & COMPONENT TESTING – MIATA, MILLENIA, MPV, PROTEGE, PROTEGE5 & 626 article. If EGR boost sensor is okay, go to next step. If EGR boost sensor does not operate properly, replace EGR boost sensor. After repair, go to step  8.
  6. Start engine. Using scan tool in SIMULATION TEST mode, simulate EGRBV OFF. Vacuum should be present for 3 seconds at vacuum hose. If vacuum is not present, go to next step. If vacuum is present, replace sensor. After repair, go to step  8.
  7. Turn ignition switch off. Remove EGR valve. Check EGR passage and gasket installation. If passage is clear and gasket is installed properly, go to next step. If passage is blocked or gasket is not installed correctly, clean out passage or replace gasket and install EGR valve. After repair, go to next step.
  8. Reconnect all connectors. Clear DTCs. See CLEARING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. Perform DRIVE MODE 1 - PCM ADAPTIVE MEMORY  and DRIVE MODE 2 - EGR MONITOR REPAIR VERIFICATION  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 complete, go to next step. If EGR system monitor is not complete, repeat this step.
  9. Using scan tool, access DIAGNOSTIC MONITORING TEST RESULTS. If TEST ID 10:41:00 value is within specification, go to next step. If TEST ID 10:41:00 value is not within specification, replace PCM and go to next step.
  10. Cycle ignition switch from off to on. Check for DTCs. See RETRIEVING DIAGNOSTIC TROUBLE CODES  under SELF-DIAGNOSTIC SYSTEM. If no other DTCs are present, testing is complete. If any other DTC is present, go to applicable test and repair.
scientia non olet · About LEMON Manuals