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What is this hose for?

11K views 13 replies 5 participants last post by  DrivenDaily 
#1 ·
Just changed the air filter in my 2012. (4 Cylinder) and I noticed this extra tube going into the air filter box. Some 2012's seem to have it, but most don't. Just curious about the function and why it isn't on all vehicles.
 

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#2 ·
You have the 2.4L I4 and I see that you're located in AZ. Do you happen to have CA emissions or something similar that changes it from a "49-state" car?
 
#3 ·
That tube goes from the air filter to the air pump for secondary air injection. I know it's on cars in states that adopted to the California emission standards. From a cold start, you'll hear the air pump turn on for 30 seconds I believe. It'll pump air into the exhaust manifold to help intercept and burn those unburned fuels.
 
#4 ·
Hey guys, thank you for the responses. I know from looking at the Carfax report this vehicle has spent it's entire life in Arizona. I'm not truly sure how our emission standards compare to California's, but I actually like having it there.

To TheSilverOne now it makes sense when I started up the engine after replacing the filter why I heard that whooshing sound you described. I guess everything is working as designed.

I appreciate the responses and the information. You guys Rock!
 
#5 ·
The actual air pump is near the starter at the bottom of the engine. A tube then goes to the back of the engine (above the exhaust manifold) where it meets with a check valve, and then into the head.

PS engines with secondary air injection vs engine without have different heads.
 

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#8 ·
Check your RPO codes for the following:

NB8 Emissions override, California
NB9 Emissions override, state-specific
NC7 Emissions override, Federal
NE1 Emissions, Arizona, Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York,
Oregon, Pennsylvania, Rhode Island, Vermont and Washington state requirements
 
#9 ·
Missing underhood decals is usually a sign of crash damage repair. Body shops don't replace them when replacing parts. Especially the engine info/certification one that is underhood. Just another thing I look for when shopping used cars.
 
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#10 ·
All other decals are in place and the front bumper cover is original, I can tell by the number of stone chips. :) The Carfax is clean too, (I know that proves nothing....) so I am not concerned about this vehicle ever being in an accident. I am just a stickler for having all my cars complete and looking like they rolled off the assembly line, so little stuff like that bugs me. I should be able to find that decal somewhere and replace it.

This Malibu is my throw-away, daily driver anyway. Just picked her up so I can keep the miles off the Stingray.
 
#12 ·
Your answer:
That tube goes from the air filter to the air pump for secondary air injection. I know it's on cars in states that adopted to the California emission standards. From a cold start, you'll hear the air pump turn on for 30 seconds I believe. It'll pump air into the exhaust manifold to help intercept and burn those unburned fuels.
 
#14 ·
If you look on Rock Auto, it should help you find it.
 
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