I have a 1999 Accord EX-V6 with 110,000 miles. About a week ago the Check Engine light came on. Tried the fuel-cap tightening, which has never solved anything for me, and it didn't this time either. So I took it to AutoZone, who read it as code P0401 - EGR Insufficient Flow. Never seen this before (or at least I don't recall it).

About a week later, before I could take it to a mechanic, I noticed that the metal flap that the the fuel pump nozzle pushes aside while fueling is completely gone -- maybe it broke off. Thinking back, I believe it's been missing for several fills. Maybe that explains why I haven't been hearing the usual "hissing" upon removing the gas cap to refuel. And maybe also why the needle doesn't move quite as far when I refuel?? (It stops exactly on F instead of going a little beyond as before).

First off, any ideas on whether these two issues could be related? It's curious that they surfaced at just about the same time. Could the EGR malfunction code be bogus, and instead reflect the missing fuel flap? And either way, is this metal flap something that really needs to be replaced? I'd imagine that the labor for that wouldn't be cheap (not that EGR work would either, depending on exactly what needs to be done). Fyi, I've never replaced the gas CAP, although it looks OK. (Unlike later models, of course, the '99 has no separate "check fuel cap" message that might have provided a hint regarding this theory.)

Any insights/suggestions would be greatly appreciated!

 

I'm wondering if the flap is #21 or #20 in the diagram below.

If it is 21, it should be pretty simple. If #20, then it will be a bit more work.

I doubt the EGR is related to the fuel cap problem. The EGR port on the intake manifold can clog up over time. Google ericthecarguy P0401for a good video on how to do this. It is for an acura TL, but you pretty much have the same engine.

 

If I'm looking at this correctly it looks like it would have been attached to the rear of part 21, and apparently broke off (probably sank into the gas tank). While I'm almost sure there was always a hinged thin metal flap there that the gas pump nozzle pushed aside while fueling, it would be helpful to have someone else confirm this, on the off chance my mind is playing tricks on me (e.g., if I'm thinking of other vehicles I no longer have).

Also, any thoughts on whether having this piece missing could lead to a bogus "EGR insufficient flow" code?

 

here's the troubleshooting for the EGR code, and no, the gas flapper is probably not related.

 

Very helpful responses. Thanks.