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DTC P0404: EGR Control Circuit Range/Performance Problem

CAUTION: When substituting or replacement of PCM is recommended, see PCM REMOVAL & REPLACEMENT  for important precautions.
  1. Turn ignition on. Using Honda PGM Tester or the HDS, do the DTC CLEAR in the CLEAR menu.
  2. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
  3. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, problem is intermittent, system is OK at this time. Check for poor connections or loose terminals at EGR valve and PCM connectors. If EGR system is not OK, go to next step.
  4. Turn ignition off. Disconnect EGR 6-pin connector. See Figure . At the EGR valve sensor side, measure resistance between connector terminals No. 1 and 2. If there is about 100K ohms, go to step  17 . If there is not about 6.3-6.7 ohms, go to next step.
  5. At the sensor side, measure resistance between EGR valve 6-pin connector terminal No. 1 and 3. If there is resistance of 100K ohms or more, go to step  17 . If there is no resistance, go to next step.
  6. Check continuity between ground and EGR valve 6-pin connector terminal No. 6 (Black wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between EGR valve 6-pin connector terminal No. 6 (Black wire) and ground connector G101. Go to step  18 .
  7. Disconnect PCM harness connector "A". See Figure . Check for continuity between ground and PCM harness connector terminal A15 (Blue/Red wire). If there is continuity, repair short in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). Go to step  18 . If there is no continuity, go to next step.
  8. Check for continuity between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). If there is continuity, go to next step. If there is no continuity, repair open in wire between PCM harness connector terminal A15 and EGR valve 6-pin connector terminal No. 4 (Blue/Red wire). Go to step  17 .
  9. Remove EGR valve and EGR plate.
  10. Clean the intake manifold EGR port with carburetor cleaner. Also clean the passage inside EGR valve with carburetor cleaner. Install EGR valve and EGR plate.
  11. Reconnect EGR valve 6-pin connector. Reconnect PCM harness connector "A".
  12. Turn ignition on. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See PCM IDLE LEARN PROCEDURE  . Go to next step.
  13. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
  14. With the Honda PGM tester or the HDS, do the EGR test in the INSPECTION menu. If the EGR system is OK, go to step  20 . If EGR system is not OK, go to next step.
  15. Turn ignition off.
  16. Replace EGR valve.
  17. Turn ignition on.
  18. With the Honda PGM tester or the HDS, do PCM RESET in the CLEAR menu. Do the PCM idle learn procedure. See PCM IDLE LEARN PROCEDURE  . Go to next step.
  19. Start engine. Hold engine speed at 3000 RPM with no loads (A/T in Park or Neutral) until radiator fan comes on, then let engine idle.
  20. Test drive vehicle under light load for about 10 minutes. Try to keep engine speed in the 1700-2500 RPM range.
  21. Check for Temporary DTCs or DTCs in the DTC menu. If DTC P0404 is set, check for poor connections or loose terminals at EGR valve and PCM harness connector. Go to step  1 . If any other Temporary DTCs or DTCs are set, troubleshoot those indicated. If there are no Temporary DTCs or DTCs set, go to next step.
  22. Using the Honda PGM Tester or the HDS, monitor OBD STATUS for DTC P0404 in the DTCs menu. If it is PASSED, troubleshooting is done. If it FAILED. Go to step  1 and recheck. If it is EXECUTING, continue driving condition until a result comes in. If it is OUT OF CONDITION, go to step  20 and recheck.
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