Alarms goes off only when car is backed in on an inclined driveway

The description sounds like it could be a faulty door or hood switch. The easiest way to tell would be to use a dealer level scan tool to read the alarm module, it stores a trigger input whenever the alarm goes off. So you could scan it and find that it says something like Left front door, or hood switch as the trigger. Any of the switches could be at fault and the scan tool would be the fastest way to determine what is the problem.

Also, while the car is sitting with the alarm on try to pull on the doors without opening them it see if the alarm goes off if so it is a weak door ajar switch inside the door. Here is how you replace the latch when you find it. Check out the diagrams (below). Please let us know what you find. We are interested to see what it is.