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Home >> Honda >> 2000 >> CR-V SE, Standard >> Repair and Diagnosis >> External Pages >> Different car >> Section 10 (Engine Controls - Self-Diagnostics - 4.3L) >> Diagnostic Trouble Code Identification >> DTC P0401: EGR System Insufficient Flow >> Diagnostic Procedures

Diagnostic Procedures

WARNING: This page is about a different car, the 2000 Isuzu Hombre. However, it is still accessible from the selected car via links, so may be relevant.
  1. Perform On-Board Diagnostic II (OBD-II) System Check. See SELF-DIAGNOSTICS - INTRODUCTION article. Retrieve and record FREEZE FRAME and/or FAIL RECORDS data for each DTC set. Go to next step.
  2. Ensure Tech 2 scan tool is installed. Start and warm engine to normal operating temperature. Run engine at greater than 1500 RPM. Using scan tool, command EGR duty cycle through 25, 50, 75 and 100 percent positions. If engine runs rough as EGR is cycled, go to step  5. If engine does not run rough, go to next step.
  3. Turn engine off. Turn ignition on, engine off. Disconnect EGR valve harness connector. Connect a test light between EGR valve control circuit (White wire) and EGR valve power circuit (Red wire) at EGR valve harness connector. If test light does not come on, go to next step. If test light comes on, go to step  7.
  4. Start engine. Using scan tool, select MISCELLANEOUS TESTS, EGR CONTROL. With test light still connected as in step  3, command EGR duty cycle increase to 100 percent. If test light comes on as EGR is cycled, go to step  8. If test light does not come on, go to step  11.
  5. Remove EGR valve and inspect valve and passages for damage. Inspect valve pintle to ensure it is not sticking partially open. If a problem is found, go to step  10. If no problem is found, go to next step.
  6. DTC P0401 is intermittent. If any additional DTCs are set, diagnose affected DTCs. If no additional DTCs are set, see DIAGNOSTIC AIDS .
  7. Check for short to ground in EGR valve control circuit (White wire). If short is found, go to step  14. If no short is found, go to step  15.
  8. Check for restriction in EGR tube or passage. If restriction is found, go to step  10. If no restriction is found, go to next step.
  9. Check for faulty electrical connection at EGR valve. If faulty connection is found, go to step  14. If connection is okay, go to next step.
  10. Replace faulty EGR valve. After replacing EGR, go to step  16.
  11. Check for an open in EGR control circuit (White wire). If an open is found, go to step  14. If an open is not found, go to next step.
  12. Check for an open in EGR power feed circuit (Red wire). If an open is found, go to step  14. If an open is not found, go to next step.
  13. Check for faulty connection at VCM. If faulty connection is found, go to next step. If connection is okay, go to step  15.
  14. Repair circuit(s) and/or connection(s) as necessary. After repairs, go to step  16.
  15. Replace VCM. Program replacement VCM. See PROGRAMMING . After replacing VCM, go to next step.
  16. Using scan tool, select DTC, CLEAR INFO function. Start engine and allow it to reach operating temperature. Using scan tool, select DTC, SPECIFIC function and enter DTC P0401. Operate vehicle within conditions required to set DTC. If scan tool displays RAN AND PASSED, go to next step. If scan tool does not display RAN AND PASSED, return to step  2.
  17. Using scan tool, select Read and Record INFO, REVIEW INFO function. If any undiagnosed DTCs are displayed, diagnose affected DTCs. If no DTCs are displayed, system is okay.
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