Ha! The EGR port is completely plugged. That could result in "insufficient flow."

2001 Honda Odyssey EGR Port Fix for P0401 Code

Our 2001 Honda Odyssey needs to pass Oregon’s DEQ to get updated license tags. Unfortunately, the check engine light wouldn’t stay off and it had code P0401 — Exhaust Gas Recirculation, Flow Insufficient.

After paying for a new EGR valve and catalytic converter (I’m not complaining, I don’t think we’ve had problems with either of these for over 220,000 miles), trying more expensive gas and gas cleaner additives, the code still showed up. Time to take matters into my own hands.

But first, I needed some information. Searching YouTube resulted in the following video:

I also found Honda’s service bulletin 00-009 which has been superseded by Honda service bulletin 05-026.

Ordinarily, any instructions that tell me to remove big hunks of metal from my car’s engine, do something to them, and then put them back on would scare me off. However, having to pay someone more money to fix my car and/or not getting my car fixed in time before the trip permit expired scared me more.

I forged ahead, basically following the method from the YouTube video, informed by the steps of the service bulletin and the torque specs and reassembly instructions from an online Chilton’s manual.

Any time I attempt a fix, I take lots of pictures and take notes so I can put it back together. Some of the pictures are attached below.

I hope to be able to update this with a picture of my OBD II checker showing no errors after a complete drive cycle.

Wish me luck!

Update: I should “clear the air” a little about where I cleaned the intake manifold. I used the carburetor cleaner in the garage with the door open, not in the kitchen sink. You don’t want to use that stuff in an enclosed space. I used the kitchen sink to rinse out the manifold when I was done with the carburetor cleaner.

Update 2: The fix worked! Woo hoo!

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Brent Logan

Engineer. Lawyer. WordPress geek. Bicycle commuter. Blood donor. Snapshooter extraordinaire.