PO476, but only during KOER test with AE
 

This has been happening for as long as I've had AE, but I'm just now getting around to asking about it...

When I run the KOER test, I always get a PO476, indicating a problem with the EBPV. The code never shows up "in the wild", only during the test. When the test is running, I can plainly hear the valve actuate, and the resulting exhaust hiss. Also, the valve works fine in cold weather, works great in my decel tune, and doesn't leak. (I rebuilt the valve when I had the turbo off a year or so ago, but the KOER test would throw the code both before and after the rebuild.

Also, all three pressure sensors (I.e. barometric sensor on the PCM, MAP and EBP) show 11.89psi, which I assume is correct for my altitude (5440ft)

So, is this a real problem, or just some anomaly with the KOER test?

Mark

I am curious as well. I need to get an AE, but I want to see where this goes. Subscribing.

Ummm... About the time I clicked "Submit", I thought of something: I wonder if this is an altitude thing, meaning the the expected EBP is lower than some preset number, and the test protocol isn't smart enough to figure out that it's low because the base barometric pressure is low due to the altitude? Have any of you other Colorado guys seen this?

Mark

No, the exhaust is tight, as I've fixed leaks at both the manifolds and up-pipes in the last couple of years, and the fixes are holding. Your idle EBP/MAP ratio matches what I'm seeing, and I think I saw something like 46psi EBP on a coffee run this morning.

Mark

Bump for the Tuesday crowd. I posted this on our club forum, too, but this place gets a lot more traffic...

Any of you with AE run KOER tests? Do you see PO476? At what altitude are you running the test?

I'd take mine to a lower altitude, but it's only been below 4000ft once in the ten years I've owned it, and getting below 4000ft means a looongg drive.

Mark

LOL! There is one place on my way home where I can get on it a little bit. EBP of 40-something PSI seems normal during moderate to slight-more-so acceleration, right? It certainly is common on mine, if not normal.

Mark