After reading 100's of posts and finally going on a 45 minute drive with constant alternating ". Key detected in vehicle" warning alternating with "rear door open" warnings and 45 minutes of constant beeping. I knew I had to come to a conclusion. Either find a fix, or drive the vehicle over a cliff.
I searched 100's of posts of people spending money, time, and energy at the dealer attempting to find a fix with very little luck among any of the posters.
. I ended up fixing the problem for 48 cents.
. I was unable to find the original post that recommended this , so that I could thank the person that came up with this idea, but I will pass it on.
First, I took electronic spray cleaner and thoroughly sprayed the inside of the rear hatch door latch. There is a small rectangular carpeted cover the can be easily removed with a flathead screw driver to allow you to spray into the latch itself. This definitely improved, but did not fix the problem. You can get electronic contact spray cleaner at Walmart or RadioShack.
You then need to buy 1/4 inch lock washers. This cost me 48 cents.
Open the rear hatch door, and on both sides of the bottom of the door you will see, rubber bumpers sticking out from the door.
Look down by the rear bumper where those rubber bumpers hit when the door is closed.
With a Phillips head screwdriver, remove the rubber washers down near the rear bumper.
Place two lock washers under each of the rubber washers to help raise them up and screw them back into place.
I have driven over speed bumps, I have gone over a curb and no alarms have gone off. Prior to this fix I could not hit a pebble in the street without an alarm going off. For a year, I have been dealing with this problem and it only took 48 cents to fix it
