Check engine lights

[Prelude99]

Recently my 99 Prelude SH check engine light came on as well as the ATTS light. I took it to Auto Zone for a free reading of codes and it came back with:

P0401 Exhaust Gas Recirculation (EGR) Insufficient Flow
P1456 Evaporative Emissions (EVAP) Control System Leakage (Fuel Tank System)

I replaced my gas cap for the P1456 since I knew my gas cap was broken anyways. The guys at Auto Zone cleared out the codes and said if the lights come back on then I need to take it to the shop. Well they came back on and since I'm broke havent been able to take it in. The lights have been on for about 3 weeks now and all of a sudden went off yesterday and havent come back on. Does that mean everything is okay or should I still take it in?

[Prelude13]

Most cases, the code is still stored even though the CEL isn't on anymore.
To get rid of it, unplug the negative(-) terminal from your battery for a good 24 hours(if you can).
I've run across too many OBD II codes, and it takes a long time for the code to be cleared without the scan tool.

Code: P0401 is EGR related.
Did you disconnect your EGR from your exhaust manifold?

[Prelude99]

Thanks!

No, I haven’t disconnected the EGR from the exhaust manifold. Unfortunately I'm a girl who doesn’t know what that means :( I keep getting the run around from the Honda dealership and repair shops. Never know who to trust. The Honda dealership said it can be one of three things and would cost me about $835 to get it fixed. Is it something I can do myself? Not completely illiterate when it comes to cars :)

So since the lights are off does that mean the problem is gone?

[Prelude13]

Yes and no.
The CEL light not being on doesn't really mean the code isn't stored...

What i can suggest, go to a different Autozone and ask them to check the codes again; let them plug in the scan tool and see if your Prelude has codes stored...if no, you're all gravy :cool:

...dont let the dealership rip you off.

Hmm..so did getting a new gas cap solve the P1456 code?

A replacement EGR valve should run you around $200.USD if your current one is faulty...just make sure your current one is indeed, kaput.
How does your Prelude drive since the code(s) popped up?
Do you feel like you have reduced fuel economy?
Or is it pretty much the same?

See, with a CEL, your car runs in "safe" mode until the ECU knows that the problem(s) are gone.





edit: OH, welcome to board! Make sure you visit our new member forum and say hello!

:redface:

[Prelude99]

Haven't had the codes scanned again since I replaced the gas cap. I'll do that today.

Well...when the codes came on I did notice a difference in the fuel economy. Also my ATTS wasn’t working. I realized that when I was taking a sharp curve...didn't go so well...hahaha. The lights just went off yesterday so I haven't noticed anything about the fuel economy but the transfer system is working again.

Can I just say that I love my car! I hope everything is all gravy :)

Thanks so much for helping!

[97 sh]

yep it is ur egr

[guti776]

yep it is ur egr

Whats the risk of running a faulty egr other than lower gas milage?
:confused:

[broncosi]

id like to know also.

My CEL was on because of the vtec controller something and one other thing that was suppose to be fixed by my mechanic. When driving, vtec wouldnt engage all the time and sometime the oil light would flash. So i put in 2 quarts and cleared the codes. After 5 mi driving it threw 1 CEL code being the EGR and not sure what to do.

Does anyone else have a prelude where the CELs always on for one thing or another? It seems like everytime i get it off it comes right back on for something else???

[mckillio]

Whats the risk of running a faulty egr other than lower gas milage?
:confused:

You will have trouble passing an emissions test, also with the EGR it's supposed to cool the air in the combustion chamber, preventing any pre-detonation. (correct me if I'm wrong on that one)

I had the same code with my '98 SH and it cost me $350 at the dealer to have it fixed, this includes having the egr valve cleaned, and having the egr ports cleaned and replugged. It's been about a week and the lights are still off.

[BadMofo]

You will have trouble passing an emissions test, also with the EGR it's supposed to cool the air in the combustion chamber, preventing any pre-detonation. (correct me if I'm wrong on that one)

I had the same code with my '98 SH and it cost me $350 at the dealer to have it fixed, this includes having the egr valve cleaned, and having the egr ports cleaned and replugged. It's been about a week and the lights are still off.

I don't believe the egr valve is supposed to cool the air in the combustion chamber (but I could be wrong about that), if anything it will be warm (since EGR stands for Exhaust Gas Recirculation, and exhaust is pretty hot). It is part of the emissions system and basically helps our environment by recirculating some of the exhaust gases that still contain unburnt fuel instead of letting them go out into the atmosphere... So yeah, you won't pass an emission test... as a matter of fact, you won't pass an emission test if your CEL is on for any reason (at least that's the way it is in NJ).

Another thing to note is that your ATTS is disabled when your CEL comes on for any reason... so if your CEL is on, your ATTS light will be on as well, and it won't work, and it will throw every single code it has...

Also, the gas cap thing is normal... On OBD2 systems, the CEL will come on if your gas cap is bad or if it doesn't get screwed on all the way after a fill up... it will then remain on for a certain amount of starts even after the gas cap is replaced/tightened. In my girlfriend's mom's car the CEL will stay on for 25 starts after the gas cap has been fixed...

I recommend that you download the 5th gen service manual, and follow the directions for unhooking your EGR valve, and cleaning it really well. You may not need a new one, and you may not need the ports drilled and replugged, you may be able to just get away with cleaning the EGR valve very well. Also, check the electrical connector (harness) that goes to it for signs of looseness/corrosion.

It's an easy DIY job, don't play into the stereotype that girls can't do the same things that guys can automotive wise! =). You can definitely do that job with little to no experience, and you will feel damn good about it after you accomplish it and save yourself a bunch of loot!