How do you program passlock system for 2004 impala?

Answer 1

I'm not entirely sure about the 04, but the 03 can be reset like this:

Ok, Engine off, doors/trunk closed, get comfy.. This will take 30 minutes.

Turn the key to the on position but don't start the engine. Wait 10 minutes. (you'll see the dash lights turn themselves off)

Within 1 minute, turn the key to the off position and back to on (again, don't start the engine) Wait ANOTHER 10 minutes. (same as before, the dash lights will turn off again)

Within one minute, turn the key off and back to the on position for the third time (almost done I promise!) when the dash turns off the third time, your key should be programmed.