I've noticed in the past that my Check Engine light (CEL) would come on due to DTC P1416 (Bank 2 Air Valve malfuction).

But lately, I've noticed that DTC P1416 is stored without the CEL coming on. What's going on? Does P1416 need to be triggered in a certain way to get the CEL to come on?

My CEL does come on when the ignition is turned on, so it's not burt out.

 

Yes, it needs to be activated 3 times before the light will illuminate.

 

Thanks for the quick reply! Guess it's not acting up quite as much as before ... but I still need to change it out someday. I've tried the air valve cleaning method a few times, but doesn't seem to last long.

 

Nope, it's a royal PITA too. I've changed my 1416 valve 2 or 3 times. The 1415 valve is readily accessible though and it's only failed once

 

Did you use the OEM check valve or an aftermarket one? I see NAPA has a replacement check valve ... wondering if it's better quality than the OEM unit.

 

Used OEM. Never thought about an aftermarket one.. but I'll def keep that in mind next time...

 

I just replaced the bank 2 check valve a couple of months ago, with an aftermarket (Standard Motor Products) valve. The original valve had a much higher resistance to flow, in the forward direction, than the replacement valve has. So far, there's been no more P1416 DTC code.

Bill Curlee has my original check valve to cut open, and try to see why they fail prematurely. I'm sure he'll report back on it when he takes it apart.

 

That would be interesting to see. I'd like to see a new aftermarket check valve cut open to compare design/construction.

 

Interesting ... were you comparing the new aftermarket check valve to a new OEM check valve, or the used messed up OEM check valve?

 

Here's the NAPA air system check valve:

Item#: CRB229000
Price: $15.69

http://partimages.genpt.com/partimages/95160.jpg

http://www.napaonline.com/masterpage...er+Check+Valve

 

Forward direction flow resistance of the new Standard # AV7 Check Valve, that I bought for a replacement, was much lower when compared to my old original OEM check valve.

The old valve didn't appear to have any rust, or other restrictions to flow, when viewed from the inlet and outlet connection ports. My guess is is that the internal diaphragm becomes stiff, after prolonged exposure to hot exhaust gases. Bill Curlee should know more after he cuts it open.

Here's a link to the Standard Motor Products AV7 valve that I used. Rock Auto had the lowest price on it.

http://www.standardbrand.com/web_app...?strSearch=AV7

 

I just got this code last night. I cleared it. How often did it come back before you decided to change this part out?

Where is this part located?
Is it easy to get to it?
If you dont change it out right away will it damage anything on the car?

 

I got tired of screwing around with mine spraying cleaner up in the hose for a year and wasnt gonna pull my intake to fix the stupid thing. So...I just unplugged my a.i.r. pump, plugged the large hose from the pump and tuned it out with HPTuners. No more codes, passed the smog machine hookup just fine and no more worries. I know most of you guys want to fix it the right way but its a useless thing to have on the car and not needed IMHO and only pre-heats the cats when cold startup occurs for about a minute or so.
Visually mine still looks all hooked up for any smog techs inquisitive eyes.

 

Replaced it 2 months ago...............no codes yet.

The Bank 2 AIR check valve is located behind the engine.

It's easy to replace if you remove the intake manifold for access to the valve.

No, it won't cause any engine damage.

 

Cleaning my valve would keep it working, and code free, for about a month.

Bill Curlee has posted a good write-up, with pictures and explanations, for cleaning it.

 

I think the air injection system works more than just at startup for a few minutes. I've had the Check Engine light come one after driving for 15~20 minutes, so it must be injecting air based on parameters while driving around.

 

Yeah my code used to come up as well 15 minutes after but was always told by several techs the pump is actually on for a min or so at startup so I dunno...Maybe it runs a check further into warmup for functioning as well but its only duty is to prelight up the cats while they are cold. I think when the valve itself sticks it throws the code as exhaust gasses are going back through to the pump or something and has nothing to do with the airpump actually working or not.

 

What actually happens is the check valve sticks and does not allow enough fresh air to be injected by the air pump into the exhaust manifold. When that happens, the O2 sensors do not react to the air injection like the computer thinks they should (because they didn't see enough fresh air), and therefore the computer sets the trouble code.

 

Yes, It does that also.
During the AIR test the PCM activates the AIR pump during CLOSED LOOP operation, which can sometimes be 10-15 minutes after a cold start.

When the AIR is activated, the PCM monitors the H02S voltages and the short-term fuel trim values for both banks of the engine.

If the AIR system is operating properly, the H02S voltages should go low, and the short-term fuel trim should go high.

If only one sensor responded, the PCM sets either a DTC P1415 or P1416 in order to indicate on which bank the AIR system is inoperative.

 

The air injection system actually injects the air into combustion chamber (from the intake or exhause side depending on car) so that the cylinder temperature can be regulated to control the production of NOx. If you live in a state there they use a rolling dyno smog (IM240) machine it does that for the sole purpose of reading NOx. This can only be checked with the car moving because other than the startup test the only time the system comes on is very light throttle cruising.

The part itself is the same generic they have been using for years. Matter of fact the first one I used was back in the late 80's from a Moroso crankcase ventilation kit, same exact part. Kind of funny its still around. My car just set this code P1416 last weekend and its very annoying to know they decided to put it behind the intake rather than down on the side of the motor as they used to do.

But bottom line is it's a part of the NOx controls of the emissions system so whether you can bypass it depends on the type of smog test you have to take or how out of wack it is. The test is usually loose enough that even if it is setting codes, as long as there are none during the test of course, that's insta fail, you can usually squeak by if its still kinda working, meaning the intermitant thing.

Again, the AIR system only purpose is to inject air into the cylinders to raise combustion temperatures to control NOx production. Annoyingly too high or too low combustion temps can cause excessive NOx. It's a real pain to tune for if the smog test checks for it. Can't go lean best power on your tune or it will read too high on the NOx and fail. Hate smog equipment.

EDIT: Just thought I should put this a different way. The AIR/EGR injection system comes on everytime you are at light throttle cruising. Which means a lot. The old tailpipe sniffer test only tested for 2 of the 3 pollutants, HC and CO. They had no way to test for the last pollutant, oxides of nitrogen or NOx. This was because there was no way to put the car into that light load cruising state. With the (IM240) rolling road dyno test now they can. So think of the combination of the AIR pump, the O2 sensors, EGR valve and the check valves as the equivalent of Catalytic Converters for the NOx system. They control how much NOx comes out the pipe. Many places even here in CA, including the one I just moved to still don't do the (IM240) NOx test, thankfully, so this may be one you can completely ignore as long as there are no codes for the smog guy to see. Hope the information helped some. The AIR system works hand in hand with the EGR system, usually components are shared. Haven't looked at my Z to see if thats the case on our cars though.