Slowly working through this still. I located the downstream O2 sensors and realized why it costs so much to replace them at the shop. Do you guys know if it's possible to replace the O2 sensor without dropping the exhaust? I'm waiting for the car to cool down before I crawl underneath to get a better look at it. The sensor plugs into the pipes after the cat. That looks pretty easy for the most part. Unplugging it from the chassis looks to be a bit harder, but should be doable with the exhaust on...right?

 

When I did mine, I used a universal O2 and spliced it into the wiring of the factory sensor. The way the wiring goes up and forward on top of that metal rail up there looks like a sonofabitch to deal with if the exhaust is in place. I'd use the universals and do all your work right there under the center of the car. They work fine and cost half of what OEM O2s cost.

 

i have the same p0411 code right now . my car starts everytime but def is running rough. i heard that it can be caused by a clogged combi valve ? im changing the vac lines tomorrow so we will see how that goes.

 

I replaced vacuum lines and actually created this problem. One of the lines was too short and crimping flow to one of the combi valves. Added a longer line that fixed it.

 

UPDATE and FIXED

I'm waiting on an OBD reader *cough* but in the mean time I've come across an old problem that's become consistently worse. Earlier on I said that the car wasn't starting every time I turned the key, but would fire up on the next try. That problem seemed to go away, but this past weekend it's become worse.

When you turn the key to start your car, the dashlights should come on. Mine aren't coming on most of the time now. There is power because if I leave the key in the RUN position, the gauges, radio, etc will come on.

If I turn the key to the point I'm about to start the car, the dashlights either don't come on, or flicker once and go out. If I then turn the key very slowly towards the OFF position, the dashlights come on. Great! But now I need to start the car. Once I edge the key forward a bit towards RUN, the lights go out and I can't start it.

Someone please tell me this sounds like the ignition switch. I replaced the switch less than a year ago so it seems odd that I'm having this issue now, but the part is between $6 and $35 so not a big deal. Tumbler too?

Thanks guys
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EDIT: It was the ignition switch. I swapped in a spare (lol?) in 14 minutes. Good to go. Thank you Jer

 

Hmm, that would be the first time I've heard of a bad ignition switch causing a p0411 code.. damn, the p0411 is such a pain in the ***. From my experience the most common causes are from a leaking SAI pump, leaking or broken combi valve or vacuum leaks. But could also be numerous other things as said above. Hopefully you get it figured out.

 

Oh that's still a problem, I just haven't had time to get to it yet It starts now at least