By taking your car to a GM Dealership. They have the special equipment to do it.
The radio on a 2003 Chevy Impala can be typically be fixed by replacing the fuse. If the radio does not work when powered, it will need to be replaced with a new unit.
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It seems you have no other choice than the stealership. See Theft-Deterrent Feature on page 3-86 of your "Owner's Manual". Something to do with the car VIN number.....
The 2003 Impala has a 17 gallon fuel tank
2003
check with your Chevy dealer on that.
Fix a "door ajar" on Chevy Impala 2003 . Still on doors closed.
In the fuel tank
antifreeze lines