CEL P0401 - Insufficient EGR Flow
 

Hi guys. My 1999 Honda Accord set the CEL P0401 code (insufficient EGR flow). I reset the CEL and it came back a few weeks later (I think it was a warmer day than the previous days). Anyways, I'm getting about 21 MPG city (I know clogged EGRs can reduce fuel efficiency), is that particularly low?

I've seen some tutorials/videos (none specific to my model). I haven't seen anything that was that good explaining the process. Also I've seen people clean out their whole throttle body / intake manifold which looks pretty complicated.

It doesn't look like I can reach 1 of the 2 bolts (the one closer to the manifold) without removing other parts out first. :( Should I just take it to the shop?

Re: CEL P0401 - Insufficient EGR Flow
 

http://www.hondaaccordforum.com/foru...-accord-31002/

and

https://honda-tech.com/forums/honda-accord-1990-2002-2/f23a4-ulev-2691467/

and

http://www.driveaccord.net/forums/sh...ad.php?t=31865

and

https://honda-tech.com/forums/honda-accord-1990-2002-2/

cleaning the throttle body valve is much easier than this in comparison

Re: CEL P0401 - Insufficient EGR Flow
 

Cleaning helps but in the end, I had to replace the EGR altogether to make my P0401 go away on my 99 accord :/ There's a cleaning procedure that requires taking off the entire intake manifold. Check that one out.

Re: CEL P0401 - Insufficient EGR Flow
 

already stated in one of the 4 links i posted

be sure to rule out the passageways and vacuum hoses first before replacing the valve

try blasting the valve itself with some carb cleaner as well

Re: CEL P0401 - Insufficient EGR Flow
 

i had the same problem on my 96 i replaced the egr and that wasnt the problem so talked to a guy that helps work on my cars and we found out that the egr ports on the intake under the fuel rail were full of carbon