: Code 0411 Secondary Air Injection

11-30-05, 07:19 PM
HI Everyone!

I know that this has come up before and I think that Omermurat (sp?) may have helped out others before but for some reason I can only find one response but I remember seeing more... I thought? I am hoping that someone can help me out here.

My CEL has come on twice in a row for this same code and Auto Zone has cleared it both times in a week... now it is on again which is making me think that there is a real problem and not just a fluke.:thepan:

I am not against trying to fix it on my own at all... I just do not have a ton of knowledge when it comes to car repairs. I actually have no clue on how to get to things or what an actuator is or what a vacuum advance does? I am fairly mechanical but just dunno where to start.:hmm:

I am wondering if I should go buy a set of the GM service manuals. Do any of you guys have them? Are they worthwhile?

Thanks in advance for all of your help!!


11-30-05, 07:43 PM
I usually buy a service manual for any car I wish to keep.
In fact I buy them for my motorcycles too, even though I rarely use them, when I need them they are worth their weight in gold.

P0411 is usually an AIR problem, depends on what kind of car we are talking about, but I have seen this a lot on certain types of vehicles and it's usually a sticky AIR check valve.

11-30-05, 08:34 PM
I am sorry - forgot to mention that it is on a 1997 Catera

Thanks in advance for any instructions


11-30-05, 08:46 PM
Do a search on this forum, aside from Omer sending out the pdf file on how to fix the problem, I made a post there on how to find out which of the components of the AIR system is at fault. The title of the thread if i am not mistaken is Check Engine light not lighting up.

11-30-05, 09:30 PM
Check the hose from the bypass valve to the pipe, see if it has a hole in it, or if you have recently repaired that hose, the valve is probably burned.

11-30-05, 09:30 PM
P0411 means that the computer is monitoring the O2 sensors, it commands the AIR pump on and watches for the 02s to switch full lean.
If the sensor continues to switch as if the AIR pump was not active it sets a code for that bank.
That code is for bank 1, which is the right bank on a Catera, the passenger's side. It's quite likely that your check valve is sticking intermittently.
Fairly common for the type of valve I have seen on that car.
I would recommend that you replace the AIR check valve.
I am not sure if there are two valves on that car, but if there are I would replace them both.
From what I can see it looks like only one, but it might be partly sticking.
There is actually a TSB regarding the '97 Catera for this concern.

Part Number

Valve, Check

11-30-05, 11:28 PM
Do a search on this forum, aside from Omer sending out the pdf file on how to fix the problem, I made a post there on how to find out which of the components of the AIR system is at fault. The title of the thread if i am not mistaken is Check Engine light not lighting up.

Hi Allen

I have read your way to diagnose the failing component without a scan tool and have kept that as it might be helpful.

Could you send me the pdf file that omer sent out earlier this year to : gtvtsmith@yahoo.com please? That would make my Saturday go a little smoother.

I dont mean to be crass... but I wouldnt know a check valve if it fell out of my car and hit me in the forehead :o It would be nice to have a document to "dumb it down" a little. :thumbsup:

Thanks a million


11-30-05, 11:48 PM
There are two valves on the 97 Catera AIR system, one is made of aluminum casing and the other one is made of plastic. I had the aluminum valve faulty, it's not closing really well, but i didn't replace it. I thought that the other valve is enough to hold back flow of exhaust going to the air pump. In my case, it's the control solenoid that is not functioning properly. I went on to replace it and the Check Engine light problem was solved. Buying two and replacing both without realizing what is the problem is not a good idea because you can just end up spending money for nothing. It's easy to diagnose which one of the many components of the system is faulty, you just have to have the time a little understanding on how the system works. Just like i said in previous post on this, all it takes is a couple or perhaps three cold starts and you'll get to the bottom of it.

12-01-05, 07:24 AM
I would agree that you need to make sure the AIR pump is operating properly, but....
A P0410 usually sets if this is the case because both banks show no AIR system response.
P0411 and PO412 are related to each bank individually, this means that typicall if one sets then the other side is working properly. That means something is not allowing the air to flow into that bank of cylinders.
While scientifically it is possible to have another problem, I have yet to see a P0411 or a P0412 that is not related to a sticking check valve.
They are not expensive at all.

In the illustration number 3 is the valve I am speaking of.
I have not had to replace one of these on Catera, but sometimes if the car has some corrosion it can be quite a challenge to get the old one loose.
If I remember correctly you'll see this valve under the intake duct on the front of the engine. It's hard to miss I think.

Barring having the diagnostic tools you'd need to accurately diagnose this concern this is what I would recommend. If you'd like to have a professional diagnose the car, that would of course be your best option, it always is.

12-01-05, 12:24 PM
I have also had the P0411 code for some time now. I now know what the valve looks like that I need to replace. Where is a good cheap place to get one?

12-01-05, 09:10 PM
Both of the valve will cost more than hundred bucks. If you have a lot of money, there is no problem but after all the problems i had with the Catera, I wanted to make sure before i spend another dime on a part replacement. And in my case, it turned out to be the Control Solenoid. If that is the case with the guy above, then he would be wasting money on the two valves and still not solving the problem. My point is, why waste money when you can be sure which part you have to replace if you will just spend a little bit of an extra time doing it.

12-02-05, 12:25 AM
Thanks A bunch for all of your help guys!

I plan on digging into this on saturday... but that depends on your next answer, I think. Are these Auto Zone/Checkers parts or would I be better off to diagnose the parts and order them online?

Just trying to analyze the best course of action in advance...

You know - worry/paranoia/spend... usually in that order! :)


12-02-05, 02:05 AM
Autozone will help you get the codes but not exactly pinpoint the problem, so you will have to decide whether to bring it to a mechanic to figure it out or do it yourself. Just like i said over and over, it's easy to pinpoint the problem, all it takes is a few cold starts which means a couple of days or three.

12-02-05, 07:07 AM
Barring having the diagnostic tools you'd need to accurately diagnose this concern this is what I would recommend. If you'd like to have a professional diagnose the car, that would of course be your best option, it always is.

Having the car professionally diagnosed and repaired is always the preferred option if you want to be right the first time and replace only the necessary parts.
Without a scan tool you are pretty lost on this one. It can be diagnosed in short order with the use of the Tech 2. (factory scan tool)

I agree it's better to test and replace one part.
This forum seems to be for people that don't necessarily have factory training and thousands of dollars of tools at their disposal for diagnosing cars.

I gave the answer I thought best suited that scenario and I stand by it.

I understand your point Allen and I am not ignoring it. I am agreeing with it but I don't know of any way to diagnose this at home to pinpoint the problem any closer. You said you have a thread out there on how to do this, I haven't read it yet. I am sure it's worth reading and I am sure that it will work.
I am a factory trained tech and my answers will always be "if you want to be sure, do it the way the manufacturer says it should be done".
Sorry if that is offensive to anyone.

12-02-05, 07:09 AM
Eagleta, I don't see aftermarket parts being an issue to resolve this kind of problem. I haven't used Autozone parts very much, but I am sure they are as reliable as any aftermarket parts.

I use factory parts, but I can't say those are any better or worse.

12-03-05, 02:05 AM
Try this link if it will work http://www.cadillacforums.com/forums/showthread.php?t=37315&page=2&highlight=Check+Engine+light . Read my last post and that will give you an idea on how to check which part is faulty. The tech 2 tool is about 2 thousand dollars, even with the dealership, not every mechanic owns one. It's the only tool you can use to diagnose which part in the system is faulty. The advantage of using the scan tool is that you don't have to do three cold starts which could easily mean three days. You can use the scan tool to command the system to operate even if the engine is warm already. The system is simple if you will try and analyze it, it's just a secondary source of air that mixes with the exhaust during cold starts to lessen pollution until the catalytic converters are warmed enough to accomplish this job. The check engine code comes up when there is not enough air coming from the AIR system which could only mean two things, a blockage in the passage way of the air coming from the pump or a leak in the system or more so a dead air pump. Just like i said in my post in the link above, if the air pump is working, which is easy to determine because you can hear it while it's running during cold start, then it makes it easier to determine which one is faulty. It could very well be either the control solenoid or the vacuum controlled check valve made of plastic. The aluminum valve, even if it's faulty can be disregarded since it's function is just to prevent the back flow of exhaust air into the AIR system. The plastic check valve, if it's working properly, can assume this function. The procedure is so easy, i wouldn't bother going to a mechanic, not until you try the procedure and replace the parts and you still get the code. Then it would be another problem. Just think about the amount of money you will be able to save doing it yourself. As an example, i had my car quoted for a mass air flow sensor replacement job, I was quoted an amount of $650.00 parts and labor. I bought the sensor for $220.00 and replaced it myself which took me 10 minutes. I am not a mechanic, I am just so pissed at the amount of labor cost and the parts cost of the Catera that i decided to do all the job myself whenever possible. I enjoy it because i learn a great deal about the car. These days, i do the oil change myself, i replaced a tie rod once, i replaced the fuel filter once, upgraded my headlights to HID including the foglights, replaced the Heater Control Valve, replaced my wipers, fixed the ghost of that sunroof that gets crazy once in a while opening itself, fixed that problem with the dual climate system where the passenger side is blowing cold air while the driver's side is blowing hot air, replaced the cabin air filter, replaced the air filter with an aftermarket one, replaced the coolant reservoir with a new one, and lots of other small things. My point is, with all these repairs and replacement, if all i did is rely on the dealership or a professional mechanic, how much do you think would have i spent already by now? The the good thing is, while doing it you learn a lot of things. All it takes is patience, time and some good sense with mechanical things (like tightening and loosening a screw here and there) and of course a place to do all these jobs. And it's funny because i did most of these jobs while my Catera is street parked. And before i forget, the most challenging job i did on the car is replaced the remote/alarm system with an aftermarket one, something with a pager and remote start (while doing it, I thought i would never get it done). And if you are going to ask where i got all the ideas from, it's from this forum and nowhere else. And remember, if you fail doing it yourself, you can always go to a mechanic.