My 1999 Accord LX (2.3 VTEC Sedan 5-speed) is throwing a P0401 test. Per the Chiltons manual, The EGR valve failed the continuity test. There was no continuity when testing between contacts 1-2, and 1-3. (Top left is contact 1, bottom right is contact 6) When +12v is applied to contact 4 and contact 6 is grounded I can hear the valve working but it makes no noticeable difference to the engine when at idle. I pulled the valve and verified that the plunger is working. When the plunger is closed, I can not blow air through it. When the plunger is open, air flows freely. There was some carbon in the ports but I did not see any blockage. Im not saying that there isnt but I didnt see any. Im torn between buying a new EGR valve because it failed the continuity test and taking the intake off for a good cleaning. I dont want to take the intake off unless I really need to and its entirely possible that there is a carbon blockage and a bad EGR valve at play here.

Are there any documents floating around out there that might be of help to me? It seems like there are TSBs in pdf format for every Accord except for mine.

Can anyone verify the EGR test results on a good EGR valve?

Any other advice besides getting a better shop manual?

 

P0401 is the code for EGR LOW FLOW.
You probably will need to clear out the port where it enters the throttle body, both sides.



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had the same problem a week ago, had honda replace the vales, and install a pipe kit as well as clean thw port for $295

 

And that was on the TSB for the V-6?

 

yeah, i think all i know is the total was 600 casue they changed the motor mounts as well for 300

 

You did notice the OP put his engine size in the post?

So are you suggesting the OP go have a V-6 upgrade kit installed on his 4 cyl??

 

I ended up taking the upper and lower intake off and cleaning them up to solve the issue. As the pictures show the upper EGR ports were clogged. I probably did not need to take off the lower and clean it out but the intake itself was filthy and I wanted to be absolutely sure I got everything.

One word of caution for anyone who attempts this. When you are under the car taking off the lower intake, be aware of the knock sensor. I had a hard time breaking one of the bolts loose of the bottom of the intake and busted the knock sensor. I turned a 16 dollars job into a 126 dollar job. On another note, when cleaning up the upper intake you want to take off the all the sensors. When the intake was put back together and I started the car, it began surging up to 3K and back to idle. It ended up being the Idle Air Control valve. I had to take it off and clean it up.

Other than that its been a week and the car runs great. Thanks for everyones help!

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Wow, yours was just as dirty as mine when I cleaned it last weekend! I didn't have enough time to take off the lower part of the manifold though...