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This is for a Northeast 98 Vulcan with the wonderful secondary AIR system normally shoehorned only into California cars, but as I understand it, was fitted to certain NE cars.

I'm once again getting a P0411 code ("the flow in the secondary air injection system is incorrect") on hot idle.

Relevant diagnostics words from the Ford Manual:
"The functional check may be done in two parts: at startup when the AIR pump is normally commanded on, or during a hot idle if the startup test was not able to be performed. The flow test relies upon the HO2S to detect the presence of additional air in the exhaust when introduced by the Secondary Air Injection system.

The DTC associated with this test is DTC P0411. "

Air flows into the manifold on cold startup so the pump and valve seem to be OK.

The code appears after driving about 20-30 minutes while idling at a traffic light or stop sign -- gotta be the "hot idle" referenced in the manual.

My question is what or where is the "H02S" ?

(I've done a search, but everyone here who uses this acronym apparently knows what it is...)
 

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HO2S = Heated Oxygen Sensor.

All of the oxygen sensors in teh Taurus have a heated wire that brings the temperature of the sensor up quicker than if they were just stuck in the exhaust pipe, thus bringing the car out of closed loop more quickly.

JR
 

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My question is what or where is the "H02S" ?

[/b]
Nemmine - found it in the manual : heated oxygen sensors.

Any easy test for the sensors? Manual has something that I don't understand about switching and output voltage...
 

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DTC Description Possible Causes Diagnostic Aides
P1411 - Secondary Air Injection (AIR) system downstream flow The secondary air injection system does not detect the presence of air in the exhaust when introduced by the secondary air injection system Electric AIR Pump
Hose from AIR pump leak
AIR bypass solenoid leak/blocked
Hose from AIR pump blocked
AIR bypass solenoid stuck open/closed
In order to test the AIR pump, it must be capable of driving the HO2S lean.


There is nothing wrong with the HO2s. It is the SAI that is bad and usually it is the relay located under the pump. It is located on the subframe under the battery. There is a small 1" hose that appears to go nowhere, this is the intake hose for the pump.
 

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There is nothing wrong with the HO2s. It is the SAI that is bad and usually it is the relay located under the pump. [/b]
That's the odd thing. I get air through the injector pipe when starting up, cold. It quits after a minute or so, so I think the pump, relay, and bypass solenoid are working, at least when cold.

The pipe from the pump to the solenoid seems to be ok.

Any idea where the pump intake is? Maybe a screen is partly clogged and I'm not getting the air flow I need.

I guess I could try cycling the solenoid (is it 5v, or 12v or something else?) when it's hot... maybe it expands and jams.
 

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Here is more info

[/b]
Thanks for the link. I just visually checked the system and discovered what must be the intake tube (short 90 degree rubber elbow pointing down) with its nose buried against/into an oil or transmission line.

It was at least 3/4 blocked by the oil line. I managed to twist it forward so its little snout is now clear. If this pump depends on free breathing, it was definitely not getting free air flow.

I have one more thing to check, then I'll reset the codes and drive around for a while.

Thanks,
Dave
 

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FWIW the PCM will see if the H20s go lean when the SAI should be running when the engine is first started. If not the PCM will try again when at a highway cruising speed. It is then when it will set a code if the sensors don't go lean.
 

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Discussion Starter #10
PCM will try again when at a highway cruising speed. It is then when it will set a code if the sensors don't go lean.
[/b]
In my case, my experience matches the description in my Ford manual -- the code light came on Sunday after a slight stumble while idling hot at a traffic light (see my OP -- the first time it came on was idling at a stop sign, waiting for our endless Northeast traffic to clear).

Anyhow, I should be able to do my next, full visual on the pipe between the solenoid and the exhaust manifold with mirror tomorrow. Right now, the car's at my wife's work right now and won't be back until after dark. Tomorrow morning, after the visual, I'll reset the code by taking off the negative terminal, then (terminal back on) drive around a couple of days to see if the SES light reappers.

Thanks, Shoz123, for all the pointers.

Dave
 

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I am a new member here and have searched for hours on this topic and can not seem to find the info I need. I have a 2000 FFV taurus. It has 38,000 miles on it. It tried some E85 and after about 100 miles got the good old P0411 code. Reset it and got it again. Test that I have run so far.
Air pump works when hooked to 12V
Vacuum is present at start then cuts off
Inspected all fittings and air hoses all real good Low miles.
Started the car and no air coming from the pump, but vacuum is present.
Does this mean that the relay to the pump could be bad? Is there any way to check this. Please any help would be great. Is there any way to check the voltage going to the air pump if the engine is warm or would I have to let it cool all the way down first? How often would the pump kick in while in the drive.
 

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P1411 - Secondary Air Injection (AIR) system downstream flow The secondary air injection system does not detect the presence of air in the exhaust when introduced by the secondary air injection system Electric AIR Pump

Hose from AIR pump leak
AIR bypass solenoid leak/blocked
Hose from AIR pump blocked
AIR bypass solenoid stuck open/closed

In order to test the AIR pump, it must be capable of driving the HO2S




Check to see if the output hose is kinked as it runs along the subframe over the tranny mount.

Also make sure the SAI solenoid vacuum line and electrical connector are secure.
 

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Thanks for the info SHOZ123.
I have gone back and retested the items you listed. I still can not get any power at the wires going to the pump. When I hook up power to it it works so I know the pump is fine. I have looked every where on the web to try and find where the relay is located and I can not find it. I found a couple of places on this site and others that give the location, but it does not apply to mine. I am not sure if it is because it is the FFV version.
Any one who know where the pump relay is located please let me knw.
 

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Here's a problem that I bet you never heard of. I got an o2 model taurus ses for my gf. I put a fuel pump in it and now it starts every try but then dies well after 3 or 4 starts it blows a hose off the side of the motor and a great amount of air escapes sounding like an air tank letting loose. Way more pressure than any vacuum hose I ever saw. The kicker is that the motor stays running as long as the air escapes but too rough to drive. Another thing to note is that with the old fuel pump the car would start and run like new when I sprayed gasoline into the intake until the vs burned off anyway. Which is the only reason I bought it. Now I'm stuck with a car that don't run and a hot blond that can't drive all that good driving my blazer please help if you think hi know what the problem could be thank you kindly
 
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