Hi Pete, thanks for the response. I have not checked that valve yet, nor has it been replaced. In going through the diagnostic steps for this code that didn't come up, which is why I never thought to check it. Could you shed a little more light on the check valve, such as where I can find it and if there are any "tricks" to replacing it? I would like to replace it today if possible. Thanks,
It is an eco tec 2.2L engine, California emissions.
Oh, that has been replaced already. That was what I referred to as the solenoid. I replaced that and the gasket as well.
The air pump does turn on at cold start. I can hear it and feel it. The old one didn't, which is why I replaced it (and hoped to solve the problem).
The vehicle does not show any symptoms via rough idle, sluggishness, anything. The only thing I could think of is the exhaust smells a little rich at start up, but I wouldn't necessarily say that's abnormal because sometimes my 2012 Rav4 does too.
Yes, desperately, please.
Ok Pete, just tried checking what you asked about. When the hose was removed I felt good flow out of it at start up. The air pump did shut off after about a minute. There was no flow from the exhaust coming out the port where the hose was plugged into. Thanks.
Yes, I still need help. Did you get my last response?
Yes, as soon as the pump turned off the flow stopped.
Yes, it is a steady stream with quite some pressure behind it. It is not what I would consider to be "insufficient" by any means.
I have a test light. I lost my scanner however. I can try to borrow one if you have a procedure you'd like me to try.
Yes, I do still need help. Thanks.
I would like to continue to wait. I still need help. Thanks.
Hi I'm Dave.
I can try to assist you, but I need to clear something up first...
I read through this thread and it appears that your air injection system is working like it is supposed to. However, I have these questions:
(1) If you do not have a scan tool, how were you planning to clear the code after the repair?
(2) If you do not have a scan tool, how do you know the problem still exists?
(3) If you do not have a scan tool, how would you know whether or not another (different) code has set since the repairs were made?
I have a simple code reader scan tool. It will read and clear codes and check for I/M but can't do anything else unfortunately.
OK. I was thinking that you had no scan tool at all. At least with that, you can clear the code and run the vehicle to see if the code comes back and/or if any other codes decide to set.
So you continue to get the same code? Also, this is the ONLY code you are getting?
Yes, constant code P0411. It is the only code that comes up too.
OK. Then we have a problem. It has come down to the fact that you do not have the proper testing equipment. It sounds like MECHANICALLY, everything is working correctly. At least PART of the electrical circuits involved seem to be working as well. Here's the problem:
This is what the service information published by the manufacturer states about this code:
Conditions for Running the DTC * more than 60 minutes has elapsed since the last cold start. * The system voltage is 9-18 volts. * The BARO parameter is more than 70 kPa. * The MAF sensor parameter is less than 33 g/s. * AIR system is commanded ON. * Conditions are stable for more than 5 seconds. * DTC P0411 runs once per trip at start up when the above conditions are met and AIR pump operation is requested.
Conditions for Setting the DTC * The difference between the predicted system pressure and the actual system pressure is more than 6 kPa. * DTC P0411 sets within 22 seconds when the above conditions are met.
1. If any other AIR DTCs are set, perform those diagnostics first.
2. Engine running, observe that the AIR Pressure Sensor parameter approximately equals barometric pressure (BARO).
3. Engine running, enable the AIR pump with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 20-25 kPa above BARO.
4. Engine running, enable the AIR solenoid with a scan tool and observe that the AIR Pressure Sensor parameter equals approximately 8-10 kPa above BARO.Circuit/System Testing
So, as you can see, you cannot perform the Circuit/System Verification without the proper scan equipment. A generic code reader cannot even check properly to see if there are any other codes present, so you cannot correctly complete step one.
Most generic OBD code readers are just what hey say they are.....
Most of them can only read GENERIC OBD codes. They cannot read "Manufacturer Specific" codes (which may, or may not be present in your vehicle). The ones that can output manufacturer-specific codes often do not render the correct code description when they do.
Then there is the fact that most of them will only access the "history" portion of the "global" or "generic" side of the computer memory. It will not access the manufacturer side as mentioned above, and it will also not access any "Pending" codes, nor will it access any "current" or "1 Trip" codes, unless they are also recorded in continuous (global) memory.
I have had MANY cars come into my shop where the vehicle owner already went to the local parts store (unbeknown to me) and had them scan the vehicle with their generic scanners.....so they THINK they already know what the problem is with the vehicle before they bring it to me. I scan the vehicle when I bring it into the shop and get the code that the customer already had, PLUS I will get one or 2 more....Trust me on this one, I fight this battle all the time when I tell the customer that there is code "Pxxxx" in their PCM and that I need to diagnose "Blah-Blah" system/circuit....and the customer GOES OFF on me saying That code was NOT in there before...YOU must have done something to my car!!! They refuse to believe that all I did was scan it with the proper equipment....
My best GUESS at this point, is that the computer is not getting the message that the pressure change has occurred - even though it is occurring....like maybe high resistance in the signal return circuit? It is not completely shorted or open, because there are separate codes for those. You really need to see what the computer THINKS is going on.
So, you need to get your hands on a scan tool that can perform the steps listed above before anyone will be able to help you any further with this problem.
Thanks for the response. I am going to have to borrow a scanner since I cannot find mine. I will run the tests as per your recommendation and check for additional codes, then tell you my findings. Thanks.
OK. You have several days to post any "follow-up" questions that you may have - even if you have "rated" the service I have provided.
Let me know what you come up with.
Ok I have a scan tool now. I will run those tests them report back. The P0411 codewas still the only one present though.
Ok just ran your tests as indicated. #1 through 3 we're as you said they should be. However on test #4 turning the air solenoid on didn't do much. The pressure was only 1 kPa above BARO at most. Could I have a faulty new part?
It is possible that your new part is defective. I get defective parts straight out of the box all the time. However, I would be more inclined to believe that the part never needed replacement to begin with.
I have copied the entire troubleshooting routine into a PDF file for you. I highlighted the part of the routine that you should be concerned with, based on your preliminary system verification test results.
Download the PDF file HERE
The file will be deleted in a few days due to copyright restrictions, so you might want to save a copy to your computer for future reference.
Do ALL of the highlighted steps. You do not want to skip over any steps if you want to avoid misdiagnosis. However, If you are getting a rise over BARO at all in step 4 of the preliminary test, my best "guess" is that you will find the problem in step 9 of the highlighted steps.
Let me know what you find.
Don't hesitate to ask if you have any more questions related to this, or need any more information.
Well, I went through all the steps you outlined. I can't seem to locate the problem still. I even went as far as replacing the solenoid with another new one just to make sure.
Where exactly is the AIR pressure sensor? Is that integrated into the solenoid? If not, if it is separate, could that be the issue? I am my wit's end here with this problem and don't know what else to do/think.
To understand the code you are getting, it might be helpful for you to know how the system that you are trying to fix is SUPPOSED to work.
Download the Air Injection System Description HERE
Please study this so you can understand the system and how it should work so you can get a better idea of why the computer has a problem with it right now. I highlighted a couple points of interest for you that very likely have to do with the problem you are trying to fix.
Note that the code you are getting basically means the PCM has detected that there is insufficient air flow through the system. Also note that in order for there to be air FLOW this implies that the air must ENTER the valve from the air pump (the pump has to be pumping a sufficient amount of air into the control solenoid) AND the air must LEAVE the solenoid and enter the exhaust system at a sufficient rate. If the air does not come into the solenoid or leave the solenoid like it is supposed to, the pressure sensor readings will not be correct and the PCM sets this code.
With this in mind, it is important to understand that a restriction on EITHER side of the control valve can cause this code. Either the air is not flowing through the system like it should due to some type of restriction, or the sensor is not getting the signal correctly to the PCM to let it know that everything is working the way it should. This could be due to a bad sensor or it could be due to sensor circuits that are not functioning like they should. Since the sensor is part of the valve assembly and the valve assembly has been replaced twice, it would be pretty safe to assume that the sensor itself (and the valve itself) is not the problem.
The preliminary test is what tells you if the problem is on the air pump side of the valve or the exhaust side of the valve....
Step 2 tells you that with the valve closed and the pump not running, the sensor is reading correctly if it is reading about the same as the BARO.
Step 3 tells you that the air pump is delivering enough pressure to the valve when you command the pump on and the sensor reads 20-25 kPa above BARO.
Step 4 Tells you if the exhaust side of the valve has a restriction. When you command the valve open, the sensor is reading the exhaust back pressure pushing back into the valve. Since your readings are very low, or near BARO when you perform step 4, this indicates that the outlet from the valve into the exhaust manifold is most likely restricted...there is not a whole lot pushing back on the valve....that is what you are looking for when it tells you that there should be 8-10 kPa above BARO. This will have the affect of not allowing the air pressure from the pump to LEAVE the valve and enter the exhaust like it should. Hence, low FLOW when the system is trying to operate normally.
I hope this is all making sense to you.
Basically, if you did the preliminary system verification correctly, you either have a restriction on the exhaust side of the valve or the sensor circuits are malfunctioning. Since the sensor reads correctly in step 2 and in step 3, I would think this to likely NOT be a problem with the sensor circuits.
I could be way off base on this, but I would be taking a really hard look at the exhaust side of the valve and check for a restriction there....carbon buildup, etc..
"Where exactly is the AIR pressure sensor? Is that integrated into the solenoid?" Yes, that is an integral part of the control solenoid. That is why there are 5 wires going into the solenoid connector. 2 of them control the solenoid and the other 3 are the circuits for your pressure sensor.
OK, I'm still stuck on this problem. I did check for a restriction, such as carbon build up. There doesn't appear to be any. I even tested all my wiring to rule out bad wires. Is there anything else you can recommend or does this seem like a bad PCM now?
If I go strictly by the information/feedback you have provided on this thread, I would say it is not likely to be a bad PCM. The PCM will either read the pressure sensor correctly or it will not. Either the pressure readings are correct during the Circuit/System Verification or they are not.
It should be noted that PCM failures are extremely RARE (although they do occur). Most PCMs that do get replaced, are replaced in error because something is missed during diagnosis and the PCM gets replaced only to find out that the new PCM sets the same code. (Just read through pretty much ANY of the online DIY auto repair forums to verify that what I am saying here is true.)
I have done my part here. I have provided the service information published by the vehicle manufacturer that will prove one way or another what the problem is with the system. There is very little more I can do for you over the internet, without having access to the vehicle to diagnose it myself.
The best recommendation I can give you at this point, is to "forget" everything you have done so far, and take the troubleshooting routine for that code and start over again from the top to make sure you have not missed something......That, and/or recruit some local assistance so you can get a second set of "eyeballs" on this project.
Well, I almost hate to admit this, but the incorrect/insufficient flow problem has been solved. When you said there had to be a restriction somewhere it got me to thinking....
When we changed the engine we had to use our old exhaust manifold. Well, we wanted to make sure there were no leaks, so we used a new gasket. The problem here was caused by the use of the incorrect gasket. While all the bolt holes lined up, it wasn't the correct gasket for a California emissions engine.
I just swapped out the wrong, new gasket for the correct, new gasket. It was clear from comparing the two that there were restrictions in the flow, as air passages were blocked. Now that I have the correct gasket on I am going to run some cold starts and be sure that the P0411 code is gone for good. I will let you know if the problem is solved once and for good, soon!
That is making PERFECT sense!
You should be able to verify the repair very easily by performing the system verification again once you have the gasket replaced. You will see the difference in step 4.
Surprise surprise, the secondary air monitor passed now! Thanks for all the help. I will be rating you later for sure.
Cool! I kinda figured that it would pass once you told me what you found. That one fit with everything we had discussed - particularly what you found in step 4 of the system verification tests. Now you know from your own experience....This is EXACTLY the reason I tried to steer you AWAY from the whole PCM thing......Now there is some hard-earned cash you get to keep in the bank!
Glad I as able to help!