Rouphis

I just finished repairing P1400 by replacing my DPFE sensor. Before replacing that sensor, P1400 was the only code stored. Now, I get P0411 after the Secondary Air Injection Monitor runs. I have never had a vechle that had AIR, so I am a bit shaky in my understanding of how it all works, and how to trouble shot the system.

Thanks
-Rouphis

Rouphis

Well, I narrowed it down a little bit. The air pump is good, and the hoses from the pump to the exhaust is good. It seems like there are 2 vacuum values, 1 check valve, and 2 solenoids.

How do I test these items? Also, where can I find a diagram with part numbers of this system?

Thanks
-Rouphis

Rouphis

Well, upon more probing, I missed a check valve, so that's 2 check valves, 2 vac controlled valves, and 2 vac solenoids.

When I first start the truck, air is being pumped into the farthest check valve from the pump(the one in the heads). After a little while, air is no longer pumping into that valve.

My plan is to use my friends mittyvac to try and test the other valve. What is the best way to test the check valves and solenoids?

Anyone???

Thanks
-Rouphis

Rouphis

Well, after finding and reading the 1996 Ford emissions manual, P0411 is a failure of the upstream portion of the self test. Since I have confirmed the function of the pump and control valve, I am replacing the check valve, assuming that based on the amount of rust inside of it, that it is not opening properly.

Thanks
-Rouphis

Rouphis

Looks like I'm still the only one posting in here, but I changed the check valve, and the problem remains, so today, I am pulling the cross over pipe, and cleaning the ports in the head.

Thanks
-Rouphis

Just call me Sean

iTrader: (1)

Sorry man, I think most of us here don't know much about OBDII since '96 is the only year in this section that has it. Thanks for posting with your testing and all.

If it works like the OBDI system (which I think it does) then the computer only sees the solenoid operating and not actual air flow through the system, so the problem most likely lies with the solenoid.

Rouphis

Acording to the Ford 1996 emissions manual, the computer throws P0411, after testing the AIR system. The system is tested by:
1. Causing a Rich condition at idle.
2. Commanding the AIR system to dump air into the heads.
3. If O2 sensors read lean, the test is passed. If no change in the O2 is detected, P0411 is thrown.

If the first part passed, the computer tests the rest of the system by calling the same rich condition and dumping air into the cat. Pass if O2 after cat reads lean, fail if no change. This would throw code P1411.

Rouphis

I looks like cleaning the heads and crossover pipe may have done the trick.

-Rouphis

memoniz

Did your light ever come back on? I have a '96 and have to deal with that P0411 code before my next inspection within the next two months. I am debating buying the solenoid or fiddling with more parts.

Rouphis

Holy back from the dead bat man.

In my case, it turns out that the PO put the heads on backwards, and on these head, instead of there simply being a plug to remove, its simply a blind hole.

One day I will work up the inspiration to swap them right way round but I have no idea when that day will come.

-Rouphis