My key fob wont unlock the doors on my 2003 impala

SOURCE: I locked my keys in

A lot of today's cars have seat backs that fold down to allow access to the trunk. I guess you would of already tried that. Just a thought. The only other thing I can think of, besides calling a locksmith, is to see if there is a blown fuse for the remote opener.

SOURCE: 2001 Chevrolet Impala Door Locks Suddenly Quit Working

Passenger side of the fender under the hood - check the fuse relay box - about $12.00 a piece - they do go bad from time to time.
exchange the power lock relay with another one and test the locks.
then put the relay back and go to the autostore.

SOURCE: I have an 06 impala and the TRUNK WON'T OPEN. It

you have a fuse for it ,check the fuse box ,it might not say trunk on fuse panel, you might need to pull those fuses out one by one checking each one to see if blown, if the center between the two sides are broke the fuse is blown, hope this helps you, thanks robert b.

SOURCE: my key wont unlock the trunk anymore but the remote opener does.

There is a cable that runs from the key cylinder to the latch mechanism. There are clips that hold the cable housing in place, and if one of those comes loose then turning the key just moves the housing without releasing the latch. Check the clip closest to the latch. To get the trunk open drop the back seat, crawl in, and pull on the cable.

It is also possible that the cable is broken or damaged and needs to be replaced -- I assume you will then need to replace the enrite assembly.

SOURCE: CHevy cobalt door locks- lock and unlock while I

Could be a problem in the shiftier. Your car doors lock automatically when you put the car in drive. They unlock when you put the car in park. The switch located in the shiftier can go bad causing the locks to randomly lock and unlock. Also, this can cause the key to get stuck in the ignition.