EGR Valve and Port (code P0401)

This is the fix for most P0401 codes due to a clogged EGR port from carbon build up. This is the cheapest step in fixing this problem before replacing parts.

When to Replace:  If van is giving you a P0401 code.
Part Needed: Carburetor cleaner
Time Needed:  45 minutes.
Difficulty: Medium

You can always purchase the complete Honda Odyssey  1999-2004 repair manual here.


  1. Remove intake manifold cover:  This is the main cover over the engine. It has four screws that you need to remove and they are 10mm. It will simply pull off once it is unscrewed.
  2. Remove rear ignition coil cover:  Remove the cover behind the manifold. It is up against the engine and has two bolts that are both 10mm.
  3. Remove 3 ignition coil connectors: Three plugs that you pull out under the ignition coil cover.
  4. Remove 4 screws on throttle body:  Remove the 4 screws on the throttle body at the right side of the motor.  There are 2 screws on the top and 2 on the bottom.  They are 12mm.
  5. Remove 3 nuts and 6 bolts on manifold:  Remove the 3 nuts inside the intake manifold and the six bolts.  These are all on top of the intake manifold. 12mm.
  6. Remove intake manifold plates:  These are both located on the left side of the intake manifold.  One is close to the engine fire wall and the other is closest to the front of the engine.  10mm.
  7. Remove boost plate: This is located on the right back side of the intake manifold.  It has 2 bolts that are 10 mm which will need to be removed.
  8. Remove IAT sensor plug: This is plugged in right beside the boost plate.  You will need to disconnect it.
  9. Remove intake manifold: The next step is to simply pull the intake manifold out of the van because you have disconnected everything from it at this point.
  10. Cover intake manifold holes:  Use duct tape to cover the intake manifold holes to keep carburetor cleaner from getting in them..
  11. Clean EGR port on intake manifold: Use the carburetor cleaner to spray in the EGR port and an 8mm drill bit (not on drill) to simply get the carbon buildup out as it is removed by the cleaner.
  12. Clean EGR port on block:  Use the carburetor cleaner on the EGR port on the block.  Clean it out the same way you did for the one on the intrake manifold you removed.
  13. Assembly:  Put the intake manifold back on the van and reassembly everything you removed.


(video by: Headswithsacks)

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