Cadillac Catera and Cimarron Forum Discussion, Check Engine light not lighting up in Past Cadillac Vehicle Discussion; cad99 & PRSPower,
The file has been sent..!
cad99, sorry for the delay.. :O)...
[B][I]Can someone send me the same file? My check engine light has came on and it is the same incorrect air flow....It was supposed to have been fixed before I got the car but I think they just cleared the code so it could pass inspection....In my state if the check engine light is on they will not inspect it so i need to find a fix for it...Thanks...firstname.lastname@example.org
I guess i have to make this post since I had the problem before and was able to figure it out with Omermurat's help. First thing to remember is that the Secondary Air injection system is initialized only during cold starts, so once the engine is warm enough it doesn't have to run. With the help of Omer's pdf file, one can easily identify the different parts that makes up the whole system. The only problem is that, in the pdf file, almost always, a scan tool is required to diagnose exactly which part is faulty. But i found a way to do it manually, but just like i said, it will require several cold starts which means you will be able to accomplish the complete diagnostics in probably 3 days of cold starting the car. The first thing you have to establish is if the air pump is okay. If you don't hear it operate during a cold start then it could be busted or probably just the relay. If you get direct power to the air pump and it runs, then it could be the relay that is not working. If you can establish that the pump runs every cold start, then you will have to move on to the other parts of the system. There are two valves in the system, one is the bell shaped aluminum valve located just before the pipes that leads to the exhaust and the other is made of plastic. If I'm not mistaken, the plastic one is called the vacuum cut-off valve. Anyway, the plastic valve opens and closes as the system is initialized. And it opens up with the use of vacuum pressure. If you look at it, there is a rubber pipe directly connected on top of it, that's the vacuum hose which connects to the control solenoid. When the system initializes, the control solenoid will let vacuum pressure through the hose and will cause the valve to open, letting air coming from the air pump through. Now, we get the dreaded engine light code because there is not enough air or there is no air that is passing through the system. Even though the air pump is running, if the valve is not going to open, air won't get through. So, to check which one among the two is faulty (Control Solenoid or the Valve), try directly connecting the vacuum hose coming from the engine into the plastic valve and try one of your cold starts and see if air will get through the valve. But of course, you will have to disconnect the big hose that connects to the other end of the valve, the one that leads to the exhaust. If after directly connecting a vacuum hose to the valve, you felt pressurized air is passing through then it should be working, try removing the vacuum hose and see if it closes back. After determining that valve is functioning properly, it is now safe to assume that the control solenoid is the faulty one. You can actually feel the solenoid clicking once the system is initialized during one of those cold starts. If the plastic valve is faulty, try replacing it first because it's cheaper and see if it will solve the problem. If replacing it will not solve the problem, then replace the solenoid. This is a long read i know, but i hope that it will give you guys an idea on how to diagnose the problem without using a scan tool. By the way, even if the aluminum check valve that i was talking about is not closing really tight, you don't have to worry about it because the plastic valve is enough to seal the system and prevent back flow of exhaust air into the air pump. Good luck
I have a 2000 Sport that I am getting an error code P0411 and have seen that you have a pdf file about how to diagnose the problem. I would appreciate your sending this file to me (email address below) or if anyone else has the pdf file I would appreciate it if you would forward it to me. Thanks.
You will need a Code reader that is used by GM technicians if you want to use the pdf file that Omer has. And not so many have that Code reader (which also sends commands to the cars computer) I just can't remember what it's called exactly. Anyway, I was able to diagnose mine when i had the problem by plainly using patience and a little of understanding how the system works. I guess i posted how I did it in this thread. You just follow what it says. Good luck
I have a check engine light on and the code is 0411. I thought it would be the idle air control valve or mass air flow sensor but now Im in doubt after reading this post. Sounds like a check valve from what I have read. If anyone has that pdf file that explains this problem a little more I would greatly appreciate it. Sgtdriggs@hotmail.com