2000 Cadillac Catera eleictrical

Electrical problem
2000 Cadillac Catera 6 cyl Automatic 132504 miles

my trunk and gas tank do not open with my key remote but the doors lock and the only way I can open my trunk or gas tank is to put my car in reverse also the stero just syop working and on my oddometer reads secerity what could be the reason for this