Code P0172

[mrNewt]

Hi guys,

Hope someone can help me on this one ...

Yesterday I got my check engine light on and this morning I went to Honda dealer. Then they said that because of the aftermarket intake I have (AEM short intake), they cannot help :/ - because when they so their tests they get "wacky" results.

Anyway, they give me the error code and they said that in order to do a proper test I have to have all original parts back on it ( :| - gtfo :( ).

Anyone has any idea what that code means?

[HBomb]

Google is your friend:

http://www.obd-codes.com/p0172

[KeithC]

I've never heard of a CAI throwing wacky codes.!!!

But then again, maybe Kenny can chime in here as he is our resident Honda Mechanic........

[mrNewt]

I did google it but got mixed answers :/ ...

Thanks HBomb, from what they say in there it might be the actual Intake lol.
I hope and pray is not one of the injectors (even though I feel there is no misfire).


Keith ... well believe it or not they literally told me they have no clue of what that code means. I find it hard to believe.

[jonweir]

We never had that problem with our K20 and AEM cold air intake.
Likely that it has set due to an airflow condition outside what is normally expected with the stock airbox.

There should also be a snapshot saved in your ECU of when the code set, so you'd be able to determine what the conditions were when it happened. Your dealer can see it with the HDS device he used to check the code (Honda diagnostic system). You could see if there were any other signal inputs that were strange (fuel injector duty, temp sensors, MAF voltage, etc.)

Suggestion after that is done: reset the code and monitor for a repeat.

[mrNewt]

Well the dealer shut me up on that one. They said they don't know what the code means and that they have no clue what is wrong and they will NOT be able to help me out untill all the stock components are in place.

So I don't think they will be willing to give me the shap snapshot. They did reset the light however.

Kind of sucks ...

[BrianL]

Just curious, but what kind of car do you have?

But, yeah the code means fuel system too rich.

[mrNewt]

Hi Brian. I have a Civic Si 08.

[TAO]

This is VERY common on the new 06+ Civic's

The MAF sensor is VERY sensitive to non laminar (Turbulent) air-flow accross the MAF sensor caused by aftermarket intakes.

The OE airbox has "vanes" arround the MAF to straighten the airflow and to keep it laminar. Aftermarket air intakes do NOT have these vanes and When MAF see's "odd" output voltage range from the non laminar airflow it throws the code.

AEM has addressed this in the latest versions of their Cold-Air (long ram) intakes with the addition of a insert that fits into the AEM MAF housing that has OE style vanes that straighten the airflow and keep it more laminar. This should limit the codes throw by the aftermarket intake
A-E-M Part number 5-304 Flow Straightener/Coupler

If your AEM is the old style, you should be able to order the insert.


This is why I custom made my own intake system that utilises the OE MAF housing (with vanes) and have a OBD scan tool that I can use ot reset the codes without going to the dealership

Moose

[mrNewt]

That's interesting Moose.
I had the feeling it might be the intake, but I wasn't sure since I have it for more then a year and nothing happened so far.

I have a short ram and do not remember what year was made, but I guess it might be 06-07. Is that considered old? :).

Anyway, thanks for the info!

[TAO]

Here is some more info and pictures ...

http://www.8thcivic.com/forums/bolt-ons-all-motor/136479-pics-aem-cai-21-519c-version-flow-straightener-coupler-fix-maf-issues.html

I know they make this for teh long ram (CAI) but I am not sure if they make it for the short ram (yours)

This straigtener came out early this year I beleive

[Slowpoke]

One of the major Subaru short ram manufacturers added a cross hatch air straightener to their intake, but I think they removed the photos of it. :)

[mrNewt]

That looks kind of cool but I have a feeling it might NOT work on the short ram intake ...
From what I see, the straightener is right before the senzor ... while on mine, if I add it to the short ram, is behind one of the curves, so the air will loose its straight trajectory anyway .. uf uf ...

Crazy question ... can I remove the straightener from the stock intake and try an fit it on the AEM intake?

[BrianL]

My god those guys on 8th gen can go on and on and on and on.......

I should point out that thread to the higher ups at work. I'm getting tired of trying to explain MAF sensor warranty....

I would tend to agree that if you install an aftermarket intake yourself, you should be on your own for figuring out why you have a check engine light (the intake/emissions system is no longer stock), but that's just my humble opinion (disclaimer).

MAFs are super sensitive, get a little bit of dirt in em and you can cause code P0171 (fuel system lean) for example (chances of this happening increase when you are installing a CAI, your aftermarket filter doesn't trap enough dirt, or not being careful when changing your filter).

[MilesM]

If you get problems again with your dealer, you can use Kenny's or MarkB's. Both HADA members and both work in the Service department. Or Downtown Acura is extremely HADA friendly. Steve Fleming is the service manager, runs a GSR and a HADA member.

[mrNewt]

My god those guys on 8th gen can go on and on and on and on.......

I should point out that thread to the higher ups at work. I'm getting tired of trying to explain MAF sensor warranty....

I would tend to agree that if you install an aftermarket intake yourself, you should be on your own for figuring out why you have a check engine light (the intake/emissions system is no longer stock), but that's just my humble opinion (disclaimer).

MAFs are super sensitive, get a little bit of dirt in em and you can cause code P0171 (fuel system lean) for example (chances of this happening increase when you are installing a CAI, your aftermarket filter doesn't trap enough dirt, or not being careful when changing your filter).


I'm sorry, I didn't want to stress anyone now.

----------------------------

Miles, thanks for the advise, I'll take that in consideration.
Thanks for the help guys!

[BrianL]

I'm sorry, I didn't want to stress anyone now.

No worries, as of Sept 15 I won't be working for Honda anymore and it won't stress me after that. Until then I'm being told that there are MAF sensor claims piling up everyday. Just saying that probably alot of them can be attributed to aftermarket parts being installed, which really shouldn't be a warranty claim. Emissions and fuel economy requirements are so tight these days compared to a few years ago that sometimes the slightest deviation from stock parts can cause a CEL (even a missing air filter!)

[TAO]

That looks kind of cool but I have a feeling it might NOT work on the short ram intake ...
From what I see, the straightener is right before the senzor ... while on mine, if I add it to the short ram, is behind one of the curves, so the air will loose its straight trajectory anyway .. uf uf ...

Crazy question ... can I remove the straightener from the stock intake and try an fit it on the AEM intake?

Possibly - I cut the Stock MAF housing out of a Stock air-box top ....it happens to have a OD that matches the ID of 3" Silicon hose ... so I just inserted it it between my OE intake tubing and my custom air-box with aftermarket cone filter.


See Picture ...


http://farm4.static.flickr.com/3113/2873652262_367cb5eaea_o.jpg

http://farm4.static.flickr.com/3210/2873652948_f2e25ce1b0.jpg

http://farm4.static.flickr.com/3090/2812246802_13d53a890b.jpg

[mrNewt]

TAO ... that is one crazy intake :). I think I will go and dismantle the stock intake :D.

[mrNewt]

Well guess what?
I think I figure it out what was the problem ... the gas station :|.

When I got the first time the light on, was 1-2 days after I have filled up (for the first time ever) from a Shell station (and yes it was the high octane).

3 weeks after the dealer story I got to fill up again from the same gas station ... 2 days later my light was on again :( (despair). As soon as I have refilled from where I usually do, light went off 10-20 minutes after I started the engine and never come on since then...

Strange coincidence or fact ... dunno. But it was interesting ...