[Evilways]

Today, while programming the nav and car was in acc mode, I heard a very audible "tap" coming from the rear of the car. I got out and listened all around until I located where the sound seemed to be coming from. The "tap" seemed to be coming from the driver side rear wheel/suspension area. It occured only while in acc mode and went away as soon as I turned off or cranked the car. It "taps" at a 2-4 second pace and there is no vibration to be found from where the sound appears to be coming from, i.e., it's not something hitting something, it's more mechanical. Anyone know what this could be?

 

[Evilways]

I just crawled under the car a bit with it in acc, there is a little bit of a high pitched sound(been there since I owned it) and the tapping, now I've narrowed it down to the center rear of the car, it seems to be coming from the area before the mufflers, a rectangle/squared silver box, pretty good size, looks like a oil pan, but is too far back(?) It stopped within 10 seconds of turning off acc and the last two "taps" were really close together. Still confused. I haven't been all under this thing like I was my 2000 TA, so I'm still learning the car. Any help is appreciated.