Recently purchased 2001 s2000 has the cel code p0411. After heavy research, I understand it is due to secondary air injection system incorrect flow. Either leaks, cracks, kinks, backward white check valve, switched up hoses or cracked air pump.

Troubleshooting done. Checked hoses 5-6 times. No obvious cracks. Hoses are hooked up correctly. Found a sloughs crack to the hose under air pump. Repaired. Air pump in good shape, no cracks. Wiring all good, pump activates at start ups.

I am all out of idea here. Ecu has een reset. Code keeps coming. Back. What else am I missing. I also hear the slave open and close so I know that's working.

I've brought it in to a mechanic. He said that the valve could ve getting stuck sometimes and could maybe use cleaning. Any idea what he means and f I could do this myself. After all the reviews about this issue, it doesn't seem to be common the valve gets sticky. I know it's not a critical error but that damn cel light is bothering me.

This post has been edited by ChaseBaciles on Sep 25 2010, 10:36 AM

 

OBD-II code P0411 means you've either put the one-way valve backwards, have a leak or loose vacuum hose or routed them incorrectly.

 

I know you said air pump was good....just double checking, I had this with a client and didnt see it at first. Pump appeared to run fine

 

You can test the vac valve by the air cleaner by powering it. It should allow vaccuum when powered, and seal shut when not. Basically it allows vac to that big valve on the bacxk of the intake.

An electrical load detector monitors pump resistance. If the values are not as expected, it will trigger P0411.

An electrical failure will trigger P0410.

Any leakage in that big valve on the back of the intake, or any sticking of the vac valve will change the values.

I got lots of those big valves if you determine it is not sealing.

 

Thanks billman. I read your post prior to checking my air pump and I specifically looked around and felt around it by taking the front bumper off. Everything all good. In thinking it's the valve sticking. Anyway to treat it before replacing the valve completely? Btw anyone have an actual pic of how the white check valve is positioned. Several diagrams are confusing.

Btw what type if electrical failure do you mean. The stem works, turns on and off during cold starts.

According to this pic here I found, my white check valve is fitted on correctly:
http://image.hondatuningmagazine.com/f/886..._Space_View.jpg

Another issue it may be is in this pic. of the solenoid valve, there is a long round item placed on top of a suction valve, in mine, it is just some sort of plastic cap that restricts suction.

http://image.hondatuningmagazine.com/f/886...enoid_Valve.jpg

vs mine:



Here are a few more pics i took in case you guys can spot something that i couldn't:

 

I think i see your problem

Take that vac cap off the valve. That is supposed to be a vent. Not plugged.

 

And put your airbox in. you are losing major HP with it removed.

 

i've tried removing it off but the code came back, ill try one more time. The other link I found with the picture of the valve has some sort of Round cap on the valve..

I didnt get the stock airbox with it

I'll be looking out for one.

 

I believe the part of the solenoid that was capped off vents the vacuum out to the atmosphere when the solenoid turns off the vacuum that opens up the air injection valve; when I had this code my solenoid lines were swapped and I heard a constant sucking noise; it almost sounded like a bearing going bad. Mine showed up after I put in a K&N FIPK - just FYI for future readers.

 

Funny thing is I suspected that cap few days back examining the hoses at work. Anyway, I took the cap off, reset the ecu. Drove it around and my idle started dipping low.. I suspected the cap was supposed to be on so I stopped and put it back on.

Anyway, I believe the RPM dipping was only due to the ecu being reset trying to re learn again. Ive reset the exu multiple times after this situation and the rpms dip low after and returns to normal after a few min. of regular driving.

Anyway, I've taken that cap off again, did a cold start and no light so far. Drove around for a few min, rpm is good again. I'll follow up the next time i do a cold start.