GM Service Manual Online
For 1990-2009 cars only

On vehicles with an automatic transmission and power door locks, the doors with automatically unlock when the shift lever is moved into (P) Park.

On vehicles with a manual transmission and power door locks, the doors will automatically unlock when the key is removed from the ignition.

The automatic unlock feature can be disabled or programmed in different ways if the vehicle has an automatic transmission and a Driver Information Center (DIC). See DIC Vehicle Personalization for more information.