I park my vehicle in my driveway on a slight upward angle. When I put the vehicle in reverse it activates the HDC fault and lowers the suspension and turns off the special programs. When the vehicle is parked on a level area no issue.. Any idea why this is happening, the vehicle is parked front up in the air slightly...

 

Typical issues causing these symptoms: battery, brake switch, brake lights, wheel angle sensor.

 

IF you have an IID tool run codes, maybe try calibrating suspension. In VERY cold weather I have gotten HDC fault and no special programs, but this was only in below freezing. Goes away on restart.

Couldn't hurt to ask a dealer about it. If they're nice they could diagnose.

 

Could also be water intrusion, front/back passenger side. Been raining a lot?

 

Yes, how could/would that effect it?

 

Main wiring trunk runs under the passenger-side carpet, front to back. Once water
accumulates more, you'll have random starting issues, EAS failure and possibly blown fuses.

Channels themself are about 2 inches deep (Same as drivers side) they can hold a good amount of water. Sunroof drains (Drivers/Passenger) & front pillars are incursion points.