Here's my story:
My AYC/ACD off light began coming on here and there but would shut off if I restarted the car. That is until one day it came on and stayed on. (In my specific case this all happened after a clutch install). I was furious I'd have to spend the $2000 for the pump and still have to go to the dealer to bleed the lines after I put it in because it can only be completely accomplished with their tool (I was told). I was confident the pump was the problem because I didn't hear it turn on when I turned the car on (I'll get to this) and upon researching the codes the car threw, it appeared the pump was shot.
IT WASNT!
While messing around with my Accessport, I saw one of the codes was for steering angle sensor. That got me thinking. I proceeded to plug in my Snap-on Versus tool, pulled up "steering angle sensor" and there was an option to "Calibrate Steering Angle Sensor". Obviously I selected the option, it ran the calibration, and low and behold after cycling the ignition the light was off! It has remained off since. Come to find out, when the system finds a problem (such as steering angle sensor not calibrated correctly) it shuts the entire system down so it doesn't even attempt to pressurize the lines and thus the pump motor never cycles.

I apologize for the novel, but I didn't want anyone here shelling out $3000 to some dealer who tells them it's their pump when all they need is their steering angle sensor calibrated or some other small part of the system replaced or repaired. A Snap-on Versus tool is more than capable of handling that as well as many other functions like the bleeding function for the lines so I imagine others may as well.

 

Moral of the story; car throws a code, get it read!

 

Mr. Delta, Thank you for this post. What a nightmare. Again thank you.

 

Thank for the info! My 9 is doing the exact same thing. Did this fix your issue? I know you stated it did but I am hoping for a longer time frame follow up to see if it really fixed the problem ans the acd lights stayed off.

 

Looks like it has. The light did come on one time when I was pulling out of a parking lot at a very slow speed, but it shut off after cycling the ignition. Since then it hasn't come on again so I'm thinking it was a fluke.