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Discussion Starter #1
Hey guys I have a 99 oddy and I have pulled these codes can you tell me what to check first?

p0420
p0401 - Insufficient flow
p1457 - emission control system leak detected
p1491 -EGR valve lift insufficent.
 

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420, 401, 1491 all are EGR related codeds and usually result in driveability problems so that should be addressed first. It really seems like an EGR Valve issue

1457 is a Evap Cannister leak issue and usually has NO drivebility related issues.

I am not personally in favour of EVAP codes turning a CKE light on for the following reason. These codes should turn on a seperate EMISSION light

The goverment has mandated the Car manufactures to develope and have a consumer maintain a system within the vehicle to capture all hydrocarbons (fuel vapours) for the life of the Car. sounds reasonable right?

Well why then does the Same goverment allow Refineries and all retailers of this gasoline to vent every tank, storage container to the AIR, so Fuel vapours are only harmfull in small quantities ?? LOL
 

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Discussion Starter #3
So what should i check first when trouble shooting the egr codes? I've already tried cleaning the throttle body and egr port. How do I check the lift in the egr valve.
 

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@ DIU I'd probably suggest an EGR valve (rockauto) should be relative chaep, its very easy to swap. disconnect battery or clear codes and see where your at.

On a 99 its probably Valve, possible wiring or controll. unless you have access to scan tool to monitor data which will give desired and auctual EGR position to diagnoss

The EGR valve is a Stepper motor, voltage is toggled by the PCM to hold or adjust it to a disered position, open, closed or anything in between, it has a sensor circuit in it to feedback to PCM on position.

Most failures are from moving to slow or the sensor circuit, some will carbon up and give a very rough idle by not closing proper

Al
 

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Discussion Starter #5
Is there a way to test the valve, it was replaced maybe 60k miles ago, I've only noticed a rough idle one time and that is all. Thanks for all the help.
 

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Search around on EGR, there's a ton of posts on cleaning the passages. It may also say how to check the EGR itself but having the passages clog up is very common. I think there's some youtube videos also.
 

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Clean the passages!!! The older style single port Honda has an EGR Pipe kit and this kit has a sleve in it that you put in the port after you drill the hole bigger then then OEM size. This will cover P0401 P1491. P0420 will be a Cat Converter 99.9% of the time thats the answer but fix the EGR problem first then see if code comes back. P1457 is a code I see all the time in 2nd gen Odysseys most likely a leak between the Evap bypass sol. valve and Two way valve. The fix is to replace both valves. Other valve I have found leaking at times is the CVS valve. Also and easy check would be the fuel cap. Make sure it is tight and and the seal is not cracked or broken. Good Luck!!!
 

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Yea I cleaned out the passages last year when I got the 420 code. It came back on a little while after. What should I do first, clean the passages again, get a new egr valve, or the new CAT?

The p1457 do I really care about this code, other than it is tripping my cel?

Do any of these codes effect gas mileage, because my gas mileage has been suffering in the last couple months.
 

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P0420 will effect your gas milage. p1457 is not a huge deal but it will keep your light on. Might take 1 day to 2 weeks before it will recode but it will come back. At this point I would be sure your egr valve is good and the ports are clean for the p0401 p1491 and replace the cat for the
P0420. I know its not cheap but if that thing comes apart and starts to block exhaust flow the back pressure can hurt your exhaust valves. Oh and when the port was cleaned was the hole drilled larger?
 

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P0420 will effect your gas milage. p1457 is not a huge deal but it will keep your light on. Might take 1 day to 2 weeks before it will recode but it will come back. At this point I would be sure your egr valve is good and the ports are clean for the p0401 p1491 and replace the cat for the
P0420. I know its not cheap but if that thing comes apart and starts to block exhaust flow the back pressure can hurt your exhaust valves. Oh and when the port was cleaned was the hole drilled larger?
P0420 will not affect gas mileage. It only means you are poluting the air.
 

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P0420 will effect your gas milage. p1457 is not a huge deal but it will keep your light on. Might take 1 day to 2 weeks before it will recode but it will come back. At this point I would be sure your egr valve is good and the ports are clean for the p0401 p1491 and replace the cat for the
P0420. I know its not cheap but if that thing comes apart and starts to block exhaust flow the back pressure can hurt your exhaust valves. Oh and when the port was cleaned was the hole drilled larger?
I can't remember if the recall was done or not when I cleaned the passages, I'll call the stealership and see if it had been done. So here we don't have emmissions, is there any harm in just gutting the cat other than polluting the air more?
 

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I can't remember if the recall was done or not when I cleaned the passages, I'll call the stealership and see if it had been done. So here we don't have emmissions, is there any harm in just gutting the cat other than polluting the air more?
No harm just might be a bit louder A lot cheeper way to go for sure
 

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Would this clear the code, or would it still throw the code?
I would think it would throw more codes if you mess with the cat to that extent. Some folks have added spark plug non-foulers to the o2 sensor with success. Others have said a thorough Seafoam treatment has helped. I would go for the EGR issue first, maybe the 420 will go away at that point. Search for that code and you'll get lots of info. As for the cat clogging, I wouldn't be too concerned about that at this point. My cat looked perfect inside when I fixed the flange bolts a year or 2 ago. Honda builds them well but the computer is pretty picky on the exhaust output.
 

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Yes it will still throw a code but google whats called an eliminator. Its a cheap system people use to remove converters and still trick the system like its normal.
 
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