P0411 Troubleshooting

[gamefanatic]

So I have had the error, like I'm sure many have had, for more than 2 years. Well, it's time to get a smog check again, but this code keeps coming back up and as one would guess fails the secondary air check. This is the only code I get.

What I have done so far:

1. Validated vacuum lines are good using hand vacuum (a few times).
2. Validated the Air Injection bypass solenoid is working both out of the car and in the car. Turns on and enables the vacuum to route to the AIRD.
3. Validated vacuum to the AIRD is more than 10 psi. (Can't remember the exact value.)
4. Validated the AIRD is working. With the car off, applied 5-15 psi to the vacuum port of the AIRD, on the Air Pump inlet I applied ~15 psi air. With vacuum applied no backpressure.
5. Validated the Air Pump is working. It was working, but I replaced it with a junk yard pull off a '99 a year ago. Every time the car starts up the pump turns on and I can feel suction.
6. Validated operation of motor by using Mode-6 command to turn it on.
7. Setup my Torque app to monitor the AIRM. At least when I'm sitting still (which is about the only time it comes on) I hear the pump turn on and off with my monitor.

I'm at a loss what to do next outside of bypassing it with a tune.

 

[SHOZ123]

Did you take the lines off that run from the diverter valve to the manifolds to make sure they are clean and open? Same with the diverter valve.

 

[99sho-time]

was the cat ypipe changed?

 

[gamefanatic]

Did you take the lines off that run from the diverter valve to the manifolds to make sure they are clean and open? Same with the diverter valve.

I wasn't able to actually remove the nut to the hot / exhaust side. But the hose going to the diverter is clean. I may have to try harder, but I know the one I got recently out of the junk yard, I had to cut out.

For what it is worth the junk yard version I cut out showed no signs of build up at all on the hot side. I validated the pressures against this so I could run shop air through the system and get a good idea of how things would flow.

 

[gamefanatic]

was the cat ypipe changed?

Nothing done to the CAT's. No apparent holes or rattling coming from there or around the O2's. Still in stock form and parts.

 

[GEN 3 SHO FAN]

My two cents (or ideas)

I have the same code now going on and off but I still hear the pump working.

I think the pump rather than stop working, could lose some power and air flow at some point. It could be old after all this time but how much mileage the '99 in scrapyard had ? (Hope not 300k.)

The other thing is something that Paul help me with recently but I remised the car just after and I cannot say if it can related but it could. I had trouble with all the IAC valves I put on mine (original, used cleaned, new, etc). I had random misfires and near stall sometimes. On mine, throttle body was a little bit too much closed and IAC valve was working on his extreme opening (or kind of). Engine seems to suffer a lack of oxygen in some situations. Openning up a little bit the TB (adjusting the stopper screw) helped me with the misfires and the near stalls.

Long story short, your mesure is taken at the cat but the oxygen coming from 2 places at the moment of the measurement (not in the SAI hoses).

Thanks you Paul by the way for all the infos you directly or indirectly gave to me. I own you some beers (a pack ?)

 

[gamefanatic]

Well I am looking into this some more this weekend. Right now I am looking to get at the AIRD and validate there is no abnormal blockage. I was excited to see from the JY part that there are two star security screws that are mounting an intermediate pipe connection. I should be able to get at those pretty easily to get it pulled out. I doubt I could find a tool to get in at the exhaust nut.

I do have my other SHO I can swap parts from that is able to pass this check. This would eliminate the possibility of a second weak pump.

If this doesn't work, I need to dig further into the computer logic like you are mentioning. As would be expected, nothing in the pinpoint tests would point to other components causing problems.

It's worth looking into the intake side of things.

 

[gamefanatic]

So I was able to fix this problem by swapping out the Air Injection bypass solenoid. I used my borescope camera to validate the AIRD was not blocked. Even though it was actuating during my tests it appears to have not been working at otger times while test driving. I'll take the win!

 

[GEN 3 SHO FAN]

Ok... Are you able to put a photo or some indication on where this solenoid is on the engine (or around of) ? As you have SLO too, are your able to say if this part is the same on SLO ? (for my personnal curiosity...)

 

[gamefanatic]

I can't say for sure if this exists on all SLO's as I don't recall seeing it when working on it, but if the AIRD valve exists, then this solenoid will exist. Maybe it only exists on the DOHC models? If it does exist, my suspicion is that it would be the same and located in approximately the same place on the backside of your intake near your other vacuum lines.

AIRD


Air Injection Solenoid (The one with the number "96" written on it):

 

[GEN 3 SHO FAN]

I ask this because my first Gen 3 SLO had a secondary air injection system. It was a crashed american Taurus reconstructed (and re-sold) in Canada, where the law are less restrictive on car damages. I remember for sure that I saw this valve on mine. On SLO, this system was probably put on all Taurus that were made for pollution restrictives states (CA, NY, etc). Other states and Canada has SLOs without it.

Accordind to what I'm seeing, other parts (on 2nd photo), the upper left one in black plastic and the other in the down right (2hoses connecting to it) are very similars to parts from Gen 3 SLOs. Parts numbers will the best to know if it's really the same parts.

As you're in CA, check if your(s) SLO(s) has the system, I'm pretty sure.

EDIT : The faulty part was the one with "96" on it.