Hi All,
I recently replaced the AOS on my 2008 3.6l V6 Cayenne, and since have had issues with the fuel system. The vehicle has 150,000 miles on it and has been a reliable daily driver.

I just replaced the fuel filter a week ago, so I started to open everything back up to see if I had not connected something properly/securely. Sure enough, one of the hoses on top of the flange of the Fuel Pressure Regulator (closest to the driver's seat, not the pressurized one) was not on securely and had popped off. Sensing an easy victory, I pushed it on correctly, got the car slightly warmed up and went for a short test drive.

Everything seemed to be fine until I wanted to go faster than 30 mph. Then, there was simply no more acceleration. I limped back home, and pulled the following codes using an iCarsoft POR V2 scanner:

P2294, (Per my online search) Problem with the Fuel Pressure Regulator Circuit (is this electrical? Hoses? Either?)
P2293, Fuel Pressure Regulator, among other possibilities.

I removed the covers and rings this time, and checked the wire and hose connections on the undersides of the flanges. I found that both the fuel filter and the fuel pressure regulator were connected correctly.

So now I am stumped. I could replace the Fuel Pressure Regulator, but I am concerned about "troubleshooting by purchasing parts", and that there is something else that may be going on.

I'll be grateful for any guidance on solving this puzzle.

Thanks,
David

 

Were you ever able to figure it out? Im having a similar issue, I have a "fuel pressure regulator circuit too high" code and have no idea why. I've replaced the hpfp, both in tank pumps, filter, and the regulator. Although the regulator was from a parts Cayenne. But the weird thing is with my original pressure regulator and even with an old right side fuel pump the car didn't have the CEL with that code for 2 days. No idea what I did that temporarily fixed it but then the cel came back on with the same high circuit code (had the code with the old regulator also) Did you ever figure your Cayenne out?

 

I ended up fixing the issue. My ecu was bad, I got a replacement one on ebay and they found a ecu cloning service.